IDOC POsting Error: Transition no. <OBJ_SYS> is blocked by another user

Hi Experts,

I m sending the XML from a third party system into SAP using XI as middleware for IDOC posting (FB01).

I m getting an error <b>Transition no. <xx> is blocked by another user</b> while sending intercompany and cash applications. SAP is unable to process such XML directly.

But if i login to SAP and mannually post the IDOC, it is getting posted successfully.

Any idea what may be the cause?

Useful answers will be rewarded for sure.

Regards

DhanyaR Nair