Why might Windows Azure CloudBlobContainer access occasionally fail with The remote certificate is invalid according to the validation procedure

Question

I am using an evaluation subscription to Windows Azure.

Occasionally when I try to access methods on a CloudBlobContainer such as GetPermissions() the web service hangs. After adding some logging I see "The underlying connection was closed: Could not establish trust relationship for the SSL/TLS secure channel. The remote certificate is invalid according to the validation procedure." in my log.

I have also had this happen when using CreateIfNotExists().

What might be causing this?

I have recently upgraded from version 1.7 to version 2 of the storage client library but still see this behavior.

Answer 1

This is not a problem that I've encountered before, but if the error message is accurate then there is something funky going on with the SSL certificate in storage. A possible work around is to just not use SSL. If your talking to a storage account in the same data centre, I don't think this will adversely affect security. You should be able to do this by just changing the https to http in your connection string.

If this does work, it might pay to contact MS support, it might point to a problem on their end.

Answer 2

I'm going to answer my own question in the hope that it is useful to someone else.

The issue was the scope of ServicePointManager.ServerCertificateValidationCallback.

It is static and effects CloudBlobContainer methods encountered after it is set.