[ms office - 2016] Outlook - Can't access shared calendar

[AGWHS]

Hi all,

 

First post, be gentle!

 

I'm having issues with a colleague's calendar, as follows:

 

• She requires full read/write access to another calendar, which up until recently has been working fine
  
• Now when she tries to add an appointment, the following message comes up:
  

 

Sorry, we're having trouble opening this item. This could be temporary, but if you see it again you might want to restart Outlook. You don't have permission to create an entry in this folder. Right-click the folder, and then click Properties to check your permissions for the folder. See the folder owner or your administrator to change your permissions.

 

I've tried fixing this as follows:

• Removed and re-added the calendar (from both the client and the calendar owner)
  
• Starting Outlook in safe mode and creating a new profile. This crashes Outlook.
  
• Looked at client's permission on the email server, but nowhere to give access to another's calendar unless it's full access to the mailbox too.
  

 

I'd appreciate any help you can give, let me know if you need any more information from me.

 

Ash