Diablo’s connection loss issue is reported to occur in all releases of Diablo, i.e., Diablo, Diablo II, Diablo III, and Diablo II: Resurrected. The error may pop out when the game is launched or during the gameplay.
The following can be categorized as the main factors causing the Diablo connection issue:
- DNS Settings of the System: If the system cannot resolve the web addresses of the Diablo servers due to the network’s DNS, then it may result in the Diablo connection issue.
- Network Restrictions: If the ISP is restricting a user’s access to the Diablo servers, then Diablo may fail to connect to its servers.
- Interference from the Security Product: If the security application is filtering the traffic from the Diablo servers in a way that the game fails to parse, then that may cause the Diablo connection issue.
- Improper Configuration of the Router or its Corrupt Firmware: An improper configuration of a router’s settings (like an old NAT-related entry or a wrong proxy entry in the router) or its corrupt firmware may cause the Diablo issue under discussion.
Perform a Cold Restart of the System and Router
A temporary communication glitch between your system and the Diablo servers may cause frequent disconnections of Diablo. Here, performing a cold restart of the system, router, or networking equipment (like a Wi-Fi extender) may solve the problem.
- Shut down the PC and unplug its power cable from the source.
- Now, power off the router along with other networking equipment (if any) and remove its power cable from the source.
- Then wait for 5 minutes and plug back the router’s power cable.
- Now power on the router and let it be properly powered on.
- Then power on the PC and launch Diablo to check if the frequent disconnection issue is resolved.
Release and Renew the System’s IP Through the Command Prompt
If the Diablo servers are blocking access to the traffic from your system’s IP, then it may result in the connection lost issue at hand. Here, releasing and renewing the system’s IP through the Command Prompt may solve the problem.
- Click Windows, search and right-click on Command Prompt.
- Now, in the submenu, select Run as Administrator and execute the following (one by one):
ipconfig /release ipconfig /renew
- Now exit the Command Prompt and launch Diablo to check if its connection problem is cleared.
If that did not work, make sure the system can communicate with the Battle.net servers by executing the following in the Command Prompt:
ping -t eu.battle.net
Try Another Mouse
If you are using a mouse that has a rapid-fire button and you are using that button to pick up the items in the game, then the “continuous” clicks from the mouse may break the game’s operation and cause the issue at hand.
- Disconnect the mouse from the system and connect a simple mouse (not a gaming mouse) with the system.
- Now launch Diablo and check if its connection lost problem is cleared.
- If not and you are using an AutoHotkey (ahk) script to automate different mouse actions, then check if disabling the AHK script solves the problem.
Delete the Battle.net Cache
If the cache of the Battle.net launcher is corrupt, it may cause the connection lost issue in Diablo. Here, deleting the Battle.net cache may clear the Diablo connection problem.
- Exit all the Blizzard-related games and close the Battle.net desktop app.
- Now, right-click on Windows and select Task Manager.
- Then make sure to end all the processes related to Blizzard (like Blizzard Update Agent or agent.exe) and right-click on Windows.
- Now select Run and steer to the following path:
- Then delete the Blizzard Entertainment folder and afterward, empty the Recycle Bin.
- Now launch Diablo and check if the connection issue is resolved.
Disable Vertical Sync (V Sync) in the Graphics Control Panel
Vertical Synchronization (aka V Sync) is a technique used by the graphics utilities (like Nvidia Control Panel) to sync frame rate between the game and display device. In some cases, this syncing operation may cause a lag in the games like Diablo and during that lag, a user action (like moving a mouse), may cause the connection loss issue. For illustration, we will discuss the process of disabling V Sync in the Nvidia Control Panel.
- Right-click on the system’s desktop and select Nvidia Control Panel.
- Now, in the left pane, expand 3D Settings and head to the Manage 3D Settings tab.
- Then, in the Global Settings of the right pane, disable Vertical Sync and apply the changes made.
- Now launch Diablo and check if its connection issue is resolved.
Roll Back the Graphics Driver of the System to the Previous Build
If the Diablo connection lost issue started to occur after a recent update of the graphics driver, then the incompatibility of the latest driver with the game or the OS may cause the issue under discussion. Here, rolling back the graphics driver to the previous build may solve the problem.
- Right-click Windows and open Device Manager.
- Now expand the Display Adapters tab and double-click on the graphics device (like an Nvidia card).
- Then head to the Driver tab and click on Roll Back Driver (if available).
- Now follow the prompts to roll back the graphics driver and once done, restart your system.
- Upon restart, launch Diablo and check if its disconnection issue is cleared. If so, then you may stop the further updating of the driver till the compatibility issue between the game and the updated driver is reported to be resolved.
If the issue persists, close all the running applications on the system, lower the system’s resolution like 800×600 (it may look a bit weird), launch Diablo, and check if the game is working fine, if so, then you may revert the resolution to your desired one.
Edit the DNS Settings of the System and Disable IPv6 of the System
If the DNS of your network cannot resolve the web addresses of essential Diablo modules, then that can cause the Diablo issue at hand. In this scenario, editing the DNS settings of the system to use another DNS server may solve the Diablo problem.
- Right-click Windows and open Network Connections.
- Now click on Change Adapter Options and in the Network Connections window, right-click on the network card in use (Ethernet or Wi-Fi).
- Now select Properties and double-click on Internet Protocol Version 4 (TCP/IPv4).
- Then, in the DNS section, enter the following values of Cloudflare DNS:
Preferred DNS Server: 184.108.40.206 Alternate DNS Server: 220.127.116.11
- Now click on the OK button and then in the Network Properties window, uncheck the option of Internet Protocol Version 6 (TCP/IPv6).
- Then apply the changes made and restart your PC.
- Upon restart, launch Diablo to check if it is clear of the connection lost issue.
Disable UPnP in the Router’s Settings
UPnP (Universal Plug and Play) is a network protocol to take care of automatic port forwarding rules for the compatible devices connected to the network. Diablo may show the disconnection issue under discussion if the UPnP feature of the router is hindering the Diablo-required traffic and ports. In this context, disabling the UPnP in the router’s settings may solve the problem.
- Open a web browser and navigate to the web portal of the router. You may have to log in using your credentials.
- Now head to the Settings tab and in the left pane, expand Security.
- Then select UPnP Settings and in the right pane, select Disable.
- Now click on Apply and then launch Diablo to check if the network connection issue is cleared.
If not, then make sure the Diablo-required ports are properly forwarded in the router’s settings, and afterward, check if that resolved the connection issue.
Try Another Network or Use a VPN
If the ISP is interfering with the traffic to the Diablo server or Blizzard is restricting access from a certain ISP (due to an ongoing security attack like DDoS), then that may cause the connection problem with Diablo. In this scenario, trying another network or using a VPN may resolve the Diablo connection issue.
- Firstly, check if using an Ethernet connection (if the issue is occurring with the Wi-Fi) solves the disconnection issue. If using a USB Wi-Fi device to connect to the Internet, check if connecting it to a different USB port of the system solves the problem.
- If not, disconnect the system from the current network and then connect to another network (like a phone’s hotspot).
- Now launch Diablo and check if it is working fine.
- If not, check if using a VPN solves the problem. If so, then you may contact the ISP to solve the connection problem.
Update the Router’s Firmware to the Latest Build
Diablo’s connection issue could be a result of outdated firmware of the router as it may have become incompatible with Diablo’s servers. Here, updating the router’s firmware to the latest build may resolve the Diablo connection issue.
- Steer to the router’s web portal through a web browser and head to the Advanced tab.
- Now, in the left pane, expand Administration and select Firmware Update.
- Then, in the right pane, click on Check to check for firmware updates. If no auto-update option is available, then you manually download and install the update.
- If an update of the router’s firmware is available, download/install the update, and once installed, restart the router.
- Upon restart, launch Diablo and check if it is working fine.
Disable or Uninstall the Antivirus/Firewall of the System
Diablo might lose connection to its servers if the security application (antivirus, firewall, etc.) is interfering with the game’s traffic and filtering out packets essential for the game. In this context, disabling or uninstalling the security software of the system may solve the Diablo problem. MacAfee and Avast are reported security products to cause the Diablo issue.
Warning: Proceed with utmost care and at your own risk as disabling or uninstalling the antivirus/firewall of the system may expose the system/data to threats.
- In the case of a 3rd party security application (like ESET), expand the hidden icons of the system tray and right-click on the security software.
- Now, in the menu shown, select Pause Protection and if a UAC prompt is shown, click on Yes.
- Then confirm to disable the security product and again, right-click on the security application in the system tray.
- Now select Pause Firewall and then confirm to disable the security software.
- Then launch Diablo and check if the connection issue is cleared.
- If not, right-click Windows and select Apps & Features.
- Now expand the security product (like ESET) and click on the Uninstall button.
- Then confirm to uninstall the security application and follow the prompts on the screen to uninstall the application.
- Once done, restart your system, and upon restart, launch Diablo and check if the connection lost issue is cleared.
- If not, check if disabling Windows Defender solves the Diablo problem.
- If the issue persists, check if clean booting the system clears out the Diablo issue at hand. If so, then you may enable back the disabled startup processes one by one till the problematic one is found. Once found, you may keep the application disabled at the system’s startup or uninstall it. Some torrent clients and Killer Ethernet Controller applications are reported by users to cause the issue. If you have any such application, you may uninstall it to solve the Diablo connection issue at hand.
Reset the Router to the Factory Defaults
The Diablo connection issue could be a result of a misconfiguration of a router setting (e.g., an old NAT-related entry or a wrong proxy entry in the router’s settings) or corrupt firmware of the router. In this scenario, resetting the router to the factory defaults may solve the problem. Before proceeding, make sure to note down the essential info/data required to re-configure the router after the factory reset.
- Locate the router’s reset button (usually, on the back or bottom of the router), and once found, press/hold the reset button with a pointy object like a paperclip.
- Now wait for 30 seconds and then release the router’s reset button.
- Afterward, wait till the router is properly powered on and re-configure it as per the OEM’s instructions.
- Now launch Diablo and hopefully, its connection interrupted issue will be cleared.