Unable to get microsoft office add ins

Hello

If you could assist me that would be great.

I get the following error when trying to add an add in:

Office Store not available

Unfortunately, your organization has disabled access to the Office Store. Please contact your administrator to request access.

I have downloaded office through my university and am logged on with my university account.

I have been to my universities IT department several times and they say I have been granted access to the office store.

I am trying to add the Mendeley Cite referencing add on that is supported by my university.

They do not seem to know what the problem is.

I am running Microsoft Word for Mac, version 16.69

On a Macbook Air 2017.

macOS Monterey version 12.6.2

Kind regards

Peter