Google has confirmed they are working on fixing a bug within Google My Business for uploading videos to your business listing. When you try to upload videos, Google is returning a "server reject error." Allyson Wright, Community Manager, Google My Business said "I can confirm that this issue has been escalated and is being looked into."
Here is the error that was posted in a Google My Business Help thread:
So if you are getting this error, no worries, Google is working on a fix.
Forum discussion at Google My Business Help.