Evolution: Permission denied on /run/user/1001

I’m trying to use Evolution to access my Ubuntu 18 systems local mail spool, but when I setup the account and try to access it, I get the following error:

Could not open mail file /run/user/1001/doc/5d761a5a/myuserid: Permission denied

I tried using flatseal to give Evolution access to All file systems and all user files, even tried adding /run/user/1001 to the “Other files” list, but still get the error.

Any suggestions?