I don't know if this is the case, but I noticed that a lot of features in Twinmotion are strictly related to the possibility to sign in:
Try to open the "file" menu to verify that you are correctly logged-in.
Another suggestion is to try to check if some functionalities in your computer don't permit Twinmotion to freely connect to internet (like firewall, Anti-virus, VPN).
I had the very same problem and by trying I found the the second option as the reason for me.
I hope this may help!