Using Lightning with Google Calendar Not Working

[EwaldFernbach]

Again, sorry for being not clear but I did start this with a new profile original post: "Here is what I did so far: start from scratch with a new Thunderbird Profile...". I renamed the profiles.ini file to profiles.bak opened Thunderbird and thus started with a new profile. At that stage everything worked as expected, i.e. I could connect to the google account and add the calendars. When I tried to connect to my second (private) google account I couldn't connect and after that I couldn't connect to the other google account anymore.
At some point I did copy the mail directories from the original thunderbird profile to the new profile. I can't remember exactly if I did that before trying to connect to the second google account or before that. Could the mail folders have an effect on the connection to the google account? How can I further diagnose this?

[WaltS48]

Sorry I missed that you tried with a new profile. As I stated previously. I have one Gmail account and don't plan on setting up another to see how that works. Using "enter your email address to create a new session" for your second profile should work. for a Google Calendar. I don't use or know how iCalendar, CalDav or Sun Java System Calendar Server (WCAP) get added. Hope you get the problem resolved.

[DN123ABC]

I have at least 6-8 people here with this same problem. I'm not about to create new email profiles for every one of them, if this is just to test something. Was hoping a bug-fix would be released by now. What is the alternative, Outlook?

[EwaldFernbach]

@WaltS48:
I am talking about a Google Calendar and have not tried anything else.
@DN123ABC the alternative for me would be Evolution although I like Thunderbird very much.

@everyone:
I am willing to diagnose and test if someone points me into the right direction. I am not afraid of terminal work and posting results to be evaluated. I am exclusively on Linux since 2008 thus my diagnosing would be limited to the Linux world.
The starting point as far as I see it is the following:
connecting to a Google calendar seems to work initially but connecting to a second account doesn't work and the initial connection is broken too as far as adding new calendars is concerned. The calendar(s) added initially synchronize and work as intended (I verified that a second ago).
The question in my mind is: "what prevents the setup of a new connection after the initial connection was made". The problem might be created by the attempt to connect to a second Google account after the connection to the initial one was successfully made.