Requested variable transaction currently locked by user &3

What causes this issue?

Variable transaction &V1& in company code &V2& is locked by user &V3&.
The lock requested by an ENQUEUE function module cannot be granted.

System Response

The ENQUEUE function module creates an exception. If this exception is
not caught by the application program, it automatically leads to
termination of the current SAP transaction.


&ACTIVITY&
Check in the lock table to see which user or which transaction is
causing the lock (Tools -> Administration -> Monitor -> Lock entries).
If necessary, consult this user.

Error message extract from SAP system. Copyright SAP SE.