Unable to post GRN. Number sequence error

GRN Journal button is not available after PO Posting.
Number sequence could not be generated because a number sequence reference is missing. Ensure that all  necessary number sequences are set up.

Number Sequence Code generates numbers that are longer than the maximum length allowed.

When applying a number sequence to EDT. If you get following error.

Go to the EDT > properties > string size > increase the string size according to the number sequence format length.