You are not authorized to post to this account

What causes this issue?

You do not have the authorization to edit the above-mentioned object.

System Response

The desired process is not executed.

How to fix this error?

Providing your entries are correct, see to it that you are given the
authorization for the authorization group specified in the account
master record and for the activity "01".
The authorization object is
F_BKPF_BES for G/L accounts
F_BKPF_BED for customers
F_BKPF_BEK for vendors

Error message extract from SAP system. Copyright SAP SE.