Since 5.5.12 install Remote Access from Remote Support session is not working

Remote Support and Access
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In a previous post, 5.5.12 and Server Verification - #20 by gchristelis, another user mentioned having the same issue. User Profile - Sat_Shah - SimpleHelp Community mentioned having emailed support and support replied stating they were working on a fix.

So, it appears this is a known bug resulting from the server verification feature and you will need to standby for a fix. There are many other ways to get the remote access service up an running and that previous thread has many of those options as well as their success or not.