The HTTP Status 500 Error is not typically an Adobe error. In contrast, it is a problem with YouTube, Vimeo, and the like, and it gets fixed at the YouTube, Vimeo, or Facebook side of things.
Until Vimeo works out the problem, can you upload your Premiere Elements 13/13.1 Timeline content to a file (AVCHD.mp4) saved to the computer hard drive and then from there upload it to Vimeo at the Vimeo web site?
Within the next few hours, I will upload a Premiere Elements 13/13.1/Windows 10 64 bit Timeline to Vimeo using the Premiere Elements built in feature. The plan is to post those results before the end of the day (within the next 6 hours or sooner).
I have had a chance to do upload of my Premiere Elements 14/14.1 Windows 10 64 bit Timeline to Vimeo using the Premiere Elements built in feature. It failed with the HTTP Status 500 message.
I did the upload of my Premiere Elements 14/14.1 Windows 7 64 bit Timeline to Vimeo using the Premiere Elements built in feature. It failed with the HTTP Status 500 message.
Because both failed, I did not continue to do these test using Premiere Elements 13/13.1.
I then exported the same Timeline content to file (AVCHD.mp4 1920 x 1080p30) and saved it to the computer desktop. Then uploaded that file to Vimeo at the Video web site.
No problems in doing that with Windows 10 64 bit.
This issue is presenting as it had in the past where it pointed to a problem at the web site which was to receive the upload from the Premiere Elements built in feature. The answer that is forced is to wait until Vimeo, in this case, corrects the server at its side.
The issue appears specific to Vimeo. There is no problem with the upload to YouTube using the same Premiere Elements 14/14.1 Timeline and the built in YouTube feature in Premiere Elements 14/14.1.
Facebook was not looked at.
More news as it developments on this Vimeo server issue.