The full error:
Error: Unable to load grid data. Invalid filter criteria.
Details: Subquery returned more than 1 value. This is not permitted when the subquery follows =,!=, <,<=,>,>= or when the subquery is used as an expression.
Multiple primary consultants.
This seems to be an issue which is caused when using the Daxtra plugin as it creates Primary consultants.
If a user gets the error: Unable to load grid data. Invalid filter criteria. Details; Subquery returned more than 1 value. This is not permitted when the subquery follows =,!=, <,<=,>,>= or when the subquery is used as an expression, please contact us via the MyAccess portal and reference the title of this article.