Filed clients return as single and received a e-file rejection because his spouse filed a return MFS with clients SSN listed as her spouse.  Client was married in October 2020, but did not inform me that he was married.  I would like to e-file the return with status as MFS, but the client can not locate his spouse to obtain her SSN.  Is there any way to e-file this return or does it have to be mailed?