Hi,
I have faced the same issue and this is because of new security parameter set for Gateway server.
Please refer to Note 1480644 - gw/acl_mode versus gw/reg_no_conn_info. You can resolve this issue by setting ABAP Parameter gw/acl_mode = 0 in your BW / BI system or following the instructions mentioned in the note .
Regards
Bhupesh Akkineni