User Defined SQL - Reports cannot be scheduled

[Cognos91]

We have custom reports, using pass-through SQL. Users can create these reports as well as run them manually. However, when they try to schedule these reports, they get the following error:

"RQP-DEF-0326 User defined SQL is not permitted for the user who has the identity '{Everyone, All Authenticated Users, Consumers, Mobile Users, Cognos Insight Users}'. "

I checked their permissions and it looks like they do have access to User Defined SQL capability. In addition, as noted in IBM, the BI package also has been granted the same capability.
We are unable to identify anything at this end.

Please do note that we control our security permissions via COgnos SDK.

Is there anything additional that needs to be looked into?