User unable to save appointment in OWA

[ErnestoMartinez]

Greetings,

I have a user who has permissions of type Editor on another user.
When trying to create a new event in this user's calendar, both via Outlook and OWA, she receives the following error:
"Could not save event".

We have checked and the user has the Editor permissions correctly assigned.
We have also checked and the "Versions" folder is not full.
He has the Archive enabled in the Exchange Management Centre and a 1 day retention policy applied.

Thank you.

[#2]

aAditionally, she gets the error and does not see the event created (even if she presses Retry), but checking the same calendar from another user with the same level of permissions, the event is created.