I have been having this issue recently where I open SMath and see that I am no longer logged in. Then when I try to log back in (I am a paying subscriber), maybe half the time it says it can't connect to server. Other times, it logs me in as normal.
"I open SMath and see that I am no longer logged in" I also see this, I vaguely associate it with attempts after reboots or after closing my laptop and reopening on another network, but I have not investigated carefully. My manual logins have always worked.