I received the same error message and am hoping the bug will be fixed on March 19. Otherwise, those choosing the pre-TCJA option (which is often more favorable tax-wise) may need to mail in their returns. What a drag!
See suggestion by @Anonymous here:
https://ttlc.intuit.com/community/taxes/discussion/can-t-efile-if-filing-8615-with-pre-tcja-rules/00/1290039
