Formula instance cannot be allocated

What causes this issue?

You tried to allocate a
<DS:GLOS.A4311EECDC4CD411AE7500A0C9EAD00F>formula allocation</> to a
formula, however, this formula allocation has already been allocated to
another formula, or the output parameters of the formula allocation
have already been completely allocated.

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?

Enter a valid formula allocation.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.