There are gaps in assignment of required role &1 &2

What causes this issue?

Either a business partner has <ZH>not </>been assigned in role &V1& &V2&
for the current object/contract or
A business partner is <ZH>not</> assigned in this role at all times in
which the object is valid (period &V3& - &V4&).
However, the Customizing settings specify that role &V1& &V2& is
mandatory for the current object/contract.

System Response

Depending on the object, you may be able to save the object despite the
fact that there is no business partner. However you will <ZH>not </>be
able to activate the contract if you have not assigned a business
partner.

How to fix this error?

Assign a business partner in role &V1& &V2& for the entire period &V3&
- &V4&.

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.