[exim] mail stuck in /var/spool/exim4/input

I'm running Debian sid and after upgrading packages today, exim stopped
working. It's keeping all my local mail in /var/spool/exim4/input and
not delivering it, and even when I type "runq" it won't deliver the
mail.

# exim4 -qff -v
LOG: MAIN
Warning: No server certificate defined; will use a selfsigned one.
Suggested action: either install a certificate or change
tls_advertise_hosts option
LOG: queue_run MAIN
Start queue run: pid=10734 -qff
delivering 1jgC7c-00028M-Af (queue run pid 10734)
R: system_aliases for marie@localhost
R: userforward for marie@localhost
R: procmail for marie@localhost
R: maildrop for marie@localhost
R: lowuid_aliases for marie@localhost (UID 1000)
R: local_user for marie@localhost
T: appendfile for marie@localhost
LOG: MAIN
== marie@localhost R=local_user T=mail_spool defer (-6): mailbox
/var/mail/ has wrong uid (0 != 1000)
LOG: queue_run MAIN
End queue run: pid=10734 -qff

# dpkg -l |grep exim
ii  exim4                                 4.92.3-1
        all          metapackage to ease Exim MTA (v4) installation
ii  exim4-base                            4.92.3-1
        amd64        support files for all Exim MTA (v4) packages
ii  exim4-config                          4.94-1
        all          configuration for the Exim MTA (v4)
ii  exim4-daemon-light                    4.92.3-1
        amd64        lightweight Exim MTA (v4) daemon

In /var/spool/mail, there's a file for in inbox, marie, with marie as
the uid and mail as the gid. This is how it's been for years. The file
/var/spool/mail itself is a link (owned by root, group root) to
/var/mail, which is also root.root.

I haven't had a single problem on my system in so long, and this has
me stumped. I appreciate anyone's help - I'd like to get my mail back
asap!

Thanks so much!!

Marie