MDS is in handshake mode; you cannot send or propose this MDS

What causes this issue?

You have sent a material data sheet (MDS) to a company. This MDS is
therefore blocked (in handshake mode) until this company accepts or
rejects it. During this time it is not possible to send or propose
another version of the same MDS to the same company.

System Response

This system does not permit you to send or propose this MDS while
another version of this MDS is in handshake mode with one of the
recipients.

How to fix this error?

Wait until the recipient accepts or rejects the MDS.

Procedure for System Administrators

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

Error message extract from SAP system. Copyright SAP SE.