Activation of condition table &1 has failed

What causes this issue?

Activation of condition table failed.
A condition table is a database table. It can only be activated if the
status is consistent.
If there are other error messages for a condition table, there is
perhaps a note for the problem.
Another reason could be that there are missing DDIC authorizations.

System Response

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

How to fix this error?

Refer to the warnings output after this message and the activation log
error messages. They describe the cause of the activation problem in
detail.
Attention: Table conversions in condition tables are dangerous, if the
table has already been used productively.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.