Not able to generate welcome letter after move-in process

Hi All,

I am trying to generate a welcome letter during Move-in process. It throws the following error:-

Error Message:- The called object is (currently) not changeable in IS-U.

Message Class - 50

Message Number - 126

The move-in process is successful but the welcome letter is not been created even when tried later same error is thrown.

Has anyone come across this type of error ? What can be the cause for this ?

Thanks in advance,

Hrushikesh.