Unable to connect to RDP session after install of ASG-RD 2018

I've been using ASG2015 without issue, every time I attempt to upgrade (2016,2017, now 2018) more than half of the connections stop working.  This time I installed 2018 fresh and manually entered several of the sessions I use.  About half of them will not connect, but will with RDS or ASG2015.  How can I determine why it will not connect?  I'm attempting to connect to Win2016 at this time...

Thanks!