Hi Mke,
(sorry for my poor english)
I've had the same problem and have solve it :
- go to 'tools' / 'option' / 'Private' and check "accept cookies" - Allways
Quit Thunderbird and run it
Enter your mail & password, check calendar and validate.
Try this ... it'was working for me
(TB 52.1.0 - Lightining 5.4.1 - Google Provider 3.3)
FM