I recently was playing around with Plastic SCM, since after all these years the perfect source control solution continues to evade us.
Overall, so far Plastic has been quite good. However, I did run into a silly user-friendliness issue that I thought I would share.
The message "The authentication or decryption has failed: server:port"
can occur for a couple of reasons.. I was running into it because the certificate hostname did not match the server hostname.
By default, Certificate Hostname is generated automatically when the Plastic SCM server is installed and matches the machine name.
Server Hostname is the address you specify in the Plastic SCM Client configuration.