No left outer join may be defined here.

What causes this issue?

You tried to insert a join.
The defined tables and links do not allow you to insert a join.
Note that the ABAP SQL statement does not support the following
situations:
The right table of a left outer join is also the right table of another
join, that is
a right table of a left outer join can only be linked with a left-hand
table;
a right table of a left outer join is the left table of another left
outer join.

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

System Response

The desired change was canceled.

How to fix this error?

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.