Hi @Tom3404,
Sorry to hear you were having some issues syncing your calendar, I can imagine that's rather annoying! Did you manage to get to the bottom of it in the end? I'm not familiar with such an error, have you tried checking on the other website's end if there are any blockers maybe?
Let us know where you're at with this one, would love to know how you got on! 🙂
Emilie