I also had this same problem. The trickiest part is figuring out which application is having the problem because the only information you get in Application Insights is xConnect for the application name.
It took me some time to figure out which role was having the problem, especially because Sitecore in Azure PaaS is somewhat new to me. Once I figured out the specific role that was having the problem (xConnect Search [Index Worker Web Job ]), it was much easier to troubleshoot.
At first, I thought it was a connectivity issue between the Azure AppService and the VM that was running Solr. Then I thought it was an issue with the SSL certificate that we were using. It wasn't until I found this KB article from Sitecore that I understood that the self-signed certificate was not trusted by the index worker.
The solution involved multiple steps:
- Find the thumbprint of the SSL certificate that you are using for Solr.
- This should already be installed in the SSL Settings of the *-xc-search App Service. It might be private, but a public key is really all you need.
- Once you have the thumbprint, you have to add that string to a config file within the Index worker
- Open up your trusty Kudu console for the xConnect Search role and browse to:
- Edit the sc.Xdb.Collection.WebClient.SOLR.xml file
- Look for the
- If this element is empty, open it i.e.
- Inside that element, add another element named
<thumbprint1> and paste your thumbprint inside.
- The thumbprint1 element should look like this:
<thumbprint1>your certificate thumbprint</thumbprint1>
- Save your changes.
- Restart the IndexWorker web job
SIDE NOTE: If you need to add multiple thumbprints, you can add additional elements by incrementing the thumbprint count i.e.