@Csaba-Ferenc-László, yes, I will try. Next time the error happens, please post the time and day here. That would help me find the problem in the logs.
Also please try this - instead of using "Reconnect account" use "Unlink account", then re-link.
I found an error in the Google logs that might be giving me a clue, but I need more time to research and test it.
BTW, it's ok to have a different email addresses for your Google Home and TRIGGERcmd accounts.
EDIT: I think I found the root cause and fixed it today, 9/12/2020 at about 12:30pm EST. You might have to re-link one more time, but after that it should stay linked.
Thank you for reporting the problem. After adding logging for this problem I see it was also affecting Alexa users.