I ran our email sending domain through an email domain health check thing, and it seems we were missing the DMARC record. I think that wasn’t as much of a thing yet when we first set this up. I’ve added it now (our email sending happens through Mailgun, DNS is with Cloudflare).
There’s also a setting that controls when we stop sending summary emails to people, the default is 180 days of no activity on the site, we had it set to 1000 days, I’ve changed it to 365 to tamper down the email volume a bit.
It does seem that after the big spam wave beginning of August things have been pretty normal again, with perhaps a smaller bump on the 22nd.
I’m hoping our reputation can naturally recover. For me (in gmail) they still seem to be landing in the inbox. The DMARC record will help as well.
I’ll make a separate post to ask people to check their spam boxes and mark any legitimate clojureverse emails as not spam, that should also help a bit.