Check this KB for some troubleshooting steps -KB4328: "Failed to retrieve certificate" - Error When Interacting With Cloud Storage (veeam.com)

I would edit the Object Storage on your VBR server and go through the wizard (Next, Next, etc) to see if this comes up to accept a new SSL or fixes it.

@Chris.Childerhose thanks a lot. However, I see no solution or fix in the kb article, just a lot of information as per usual. What is the actual fix here. All required ports are open on the server, all other db files are backed up via "file level" backup  to AZURE and onsite, but not the exchange server db file which is currently being backed up with no errors via BUEXEC 21.1

What is the actual fix here?

At this point I am not sure and it would be best to open a Support ticket to get further assistance.  They can look at the logs better than most folks here.

@Chris.Childerhose 

“I would edit the Object Storage on your VBR server and go through the wizard (Next, Next, etc) to see if this comes up to accept a new SSL or fixes it.” - I see no such option in my veeam object storage/Azure under backup repositories

@Chris.Childerhose thanks, i will try them as this is very strange, every other db file is uploaded to the azure object storage but no the exchange db file.

Ok.  It was just a shot at trying something hopefully support can assist further.

https://www.findbugzero.com/operational-defect-database/vendors/veeam/defects/kb4328

Could this be legit and/or me experiencing above?

I am sure if this was an issue Veeam would have addressed it.  To me it is not legit based on that page.