Resolved: Error: A special Rpc error occurs on server [servername]: The source data is corrupted or not properly Base64 encoded

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Friday, while building a new lab to use while writing a chapter for our new Microsoft Teams book, I went through the normal process in Exchange to request a certificate and apply it.  Easy peasy normally, right?

It should have been.  I was able to quickly resolve it, but I thought I’d share my quick tale of woe.


After building my oh-so-vanilla Exchange server (I believe the technical term is Next, Next, Finish), I was feeling particularly lazy and went through the Exchange Admin Center to request a certificate.  I plopped in my details, and then took the text of the resulting CSR and pasted it into Digicert’s tool.

For the record, I requested a wildcard cert from Digicert (*, if you must know).

Anyway, a few minutes later, I received an email notifying me of my certificate’s completion.  I proceeded to log into the Digicert web portal and downloaded the file, saving it to my newly-minted Exchange server.

I navigated back to the EAC and browsed to the cert.  And then, this:

A special Rpc error occurs on server [servername]: The source data is corrupted or not properly Base64 encoded.

Seems like a good time to invoke Wanda:

Don’t worry. I figured it out.  And you can, too.


As it turns out, I had downloaded the completed certificate in the .PEM format, including all certificates in the chain.

So, at this point, there were two possible solutions:

  • Go back to Digicert and download it in a different format (obviously, the easier solution, but we’re in technology, and everyone knows that’s not how we roll)
  • Edit the PEM file

In my case, I just deleted the last two certificates (everything from the second —–BEGIN CERTIFICATE—– line down), saved, and retried the import.  Viola!

Note: if your server doesn’t already trust the issuing certificate authorities, you may want to go back and download a certificate bundle that has them all and import it.

Until next time,



Published by Aaron Guilmette

Helping companies conquer inferior technology since 1997. I spend my time developing and implementing technology solutions so people can spend less time with technology. Specialties: Active Directory and Exchange consulting and deployment, Virtualization, Disaster Recovery, Office 365, datacenter migration/consolidation, cheese. View all posts by Aaron Guilmette

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