Query to polybase external table giving error "Access to the remote server is denied because no login-mapping exists." we have successfully created all pre-requisite of creating external tables using SQL Server 2017 Standard Edition CU22 Polybase.
The issue we have is the non-sysadmin login can't query those external tables .It shows below error.

Msg 7416, Level 16, State 2, Line 29
Access to the remote server is denied because no login-mapping exists.

The sysadmin login can query external tables without any issue.
Is there anybody saw this issue and can help to resolve it.
I don't know if this is directly related to your issue but the known limitations on PolyBase state that:

In order to use PolyBase, you must have sysadmin or CONTROL SERVER
level permissions on the database

As such you might try to:
GRANT CONTROL SERVER TO [LoginName]

However know that CONTROL SERVER gives you many rights on the instance such as the right to initiate a shut down.