&1 &2: Start constraint conflicts with a successor date

What causes this issue?

When backward scheduling the project element, the system calculated a
start date based on a successor relationship and the duration of the
project element. This start date occurs before the fixed start of the
project element.

System Response

The system ignores the successor relationship and defines the fixed
start date as the calculated start of the project element. The system
calculates the finish date from that point onwards using the duration of
the project element.

How to fix this error?

Check whether the fixed start date is realistic.

Procedure for System Administrators

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

Error message extract from SAP system. Copyright SAP SE.