Occasionally, customers may see the following errors in their event logs:
Message: Synchronization Error in Request
InnerMessage: The underlying connection was closed: An unexpected error occurred on a receive.
InnerStackTrace: at System.Net.HttpWebRequest.EndGetResponse(IAsyncResult asyncResult) at DotNetNuke.Professional.Providers.CachingProviders.WebRequestCachingProvider.WebRequestCachingProvider.OnSynchronizeResponseCallback(IAsyncResult asynchronousResult)
This error is generally caused by having multiple servers set as active when the site is only using a single server. Having multiple servers set as active will result in the site believing that it is a web farm and sending out requests to synchronize the cache between the active servers
Requirements: SuperUser access to the DNN instance
1. Log in to your DNN instance with SuperUser credentials.
2. Go to Persona Bar > Settings > Servers > Server Settings.
3. On this page, you will see a list of servers. Two or more of them will be active and enabled. You will need to delete all servers that aren't currently hosting your site.
- If you are unsure which server is hosting your site, go to Persona Bar > Settings > Servers > System Info and click on the Web tab. The Host Name listed here will be the correct one.
4. Clear your cache.
5. Validate the fix by monitoring the event logs. If successful, the error will not show up moving forward.