The user is not able to raise a request for Catalog item from service Catalog

[PV]

So i got this incident in which user says he can't raise request for a catalog item. That item is FTSD general assistance. the error is "the item in cart is invalid or you're not authorised".

Can someone guide me on how to approach here 

[PV]

The user is trying to submit req from instance, as he works in another department/group. The catalog item is available to a single group (field service desk users) and he is part of that group and still not able to raise request that's the issue. Suggest something now

[Ruchit]

Can you please check the User Criteria on that catalog item. Please check if that specific user has that access.