The issue is that this is knocking people’s website’s “offline” if they have setup Apache2 with it’s default OCSP stapling settings at least on Firefox (Chrome doesn’t do OCSP iirc, so I don’t know how it’ll react). Refreshing multiple times helps of course, since the server will continue to attempt to get a valid response, but the average user will probably resign before that happens.
There is a workaround available here at least if you don’t use the “OCSP Must Staple” extension: OCSP error is taking down my site in firefox
Sadly the error message from Firefox sugggests a server configuration error, which is strictly speaking not quite correct.
There is no information on https://letsencrypt.status.io/ either, which further obfuscates the source of the issue.