4026 This error is caused by an incomplete shutdown of a previous XRC session, and can be associated with a system abend. If the ANTASnnn address space is active, cancel both it and the ANTAS000 address space. Reissue the XSTART or XRECOVER command. If the problem persists, generate a dump (if possible) of the ANTAS000 and ANTASnnn address spaces.
Do you know Concurrent Copy (CC) and XRC are entirely different things? You can sometimes get clashes between the two, especially if CC leaves a hanging session in one of the LCU's. Have a look at the LISTSESS and LISTDVCS commands in the Advanced Copy Services manual that help you identify errant sessions. CC ones start Cxxx and XRC ones Xxxx. Sometimes you have to terminate hung CC sessions as they can corrupt the 'side-files' in the controller cache.