Internal error & during reading of adjustment data (Notify system adm.)

What causes this issue?

An internal error occurred whilst the adjustment data was being read
(probably a program error).

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?

You cannot correct the error yourself. Inform your system
administrator.

Error message extract from SAP system. Copyright SAP SE.