Chosen object & & & is blocked by user &

What causes this issue?

The object you want to access is being processed by another user or you
are blocking it (in another session).

How to fix this error?

Check whether you are blocking the object yourself (in another
session). If so, terminate your processing in that session.
If another user is blocking the object, wait a moment and then
re-access the object.

Error message extract from SAP system. Copyright SAP SE.