RFC issue

Hello all,

I have created new FM 'X' in which i am calling another FM 'Y'(which is remote enabled but calling in same system ) to change PO data, when i run the FM 'Y' in SE37 it is changing PO in back end and no issues . But when i execute my new FM 'X' PO is not changed and FM 'Y' is giving error messages.

Please let me know what is the difference .