Excel 365 Proplus formulas not wokring

I have received an update on 365 and now the formulas are not accepted anymore.

Especially the formulas in which criteria are used.

for instance countif( rnage. criteria)

Previously in the criteria I could enter for instance "O" as value, now this is not excepted.

Even cell reference like N3 is not accepted.

Using the formula wizard in the toolbar results in the same error.

Does anybody know how to solve this?

Thanks

David