NWBC timeout issue when creating Material in MDG

Hi Experts

We are using NWBC 4 PL 10 for creating materials in MDG. We enter a material number and click twice on "continue". We get the following error message briefly after clinking "continue" for the second time:

"500 SAP Internal Server Error

ERROR: User session (HTTP/SMTP/..) closed after timeout (termination: ERROR_MESSAGE_STATE)"

This error disappears after about 10 seconds and then displays the "Material: New" screen.

This is an annoying error that we can't seem to solve.

We do not get this error when using transaction NWBC from SAP.

Any suggestions?

Regards

Danie