Hello @SarveshI 

Do they already have access to the records they want to see the report on..?

Try by giving either the report_view ACL on the Table to snc_external users....

(Or)

You need to give Dashboard access as well as individual reports in access to snc_external users.

On the top right hand side of dashboard/report, you will have to share to snc_external role....

even with that, there's a chance it might not work as they should also be having report_user role to read the reports...

Please mark the answer as helpful and correct if helped. 

Kind Regards,

Ravi Chandra