cannot accept an inbox share invitation

[eustachy]

Hello

I have a problem with accepting share invitations.I was using version 5.0.14. I send a share invitation to one acconaunt, and there wasn't problem. Then few moment later I want to send invitation to other acconount, and there was a problem. Mail with invitation is reach this acconaount, but there was an accept button in it.
I find this thread <click>,and following sugestion I upgrade my zcs to newest 5.0.16, but I have still the same problem.

Thanks for help
Rafal