I believe the reason for that is the user maintained for destination ECC in transaction SM59 isn't a dialog user.
Assign a dialog user under the Logon Tab(in SM59 for ECC) and you shall be able to proceed.
I believe the reason for that is the user maintained for destination ECC in transaction SM59 isn't a dialog user.
Assign a dialog user under the Logon Tab(in SM59 for ECC) and you shall be able to proceed.