SSL problems
If UpStream comments don’t appear in the front or admin area of your site, the most likely issue is a wrongly configured SSL certificate.
If comments don’t show, make sure your entire site is running over either http or https.
If your site switches between http and https (whether accidentally, or on purpose), that can cause problems with comments.
Problems with Administrator comment
It’s been reported that the Advanced Access Manager plugin needs a small tweak to work with UpStream.
If Advanced Access Manager is installed, then Administrator accounts may be not be fully operational in the UpStream Comments area.