Some people cannot send me calendar invitation

[laurent]

I do use Cloudron's mail and calendar server ...

[nebulon]

Can you give more info on that, a calendar invitation is just a special email with a certain attachment as far as I know. There is nothing the mail server does itself with this. Have you tried to use SOGo or such with that mailbox?

[laurent]

I think your solution for my "bad reputation OVH server IP" problem did the truck. Thanks @nebulon