Same here. One of the applications I use for a long time obviously tries to validate a letsencrypt certificate via OCSP. Looks like a false entry has made it to the internal ESET blacklist.
As of this morning i'm getting a lot of alerts across the orginization for:
hxxp://ocsp.int-x3.letsencrypt.org/MFMwUTBPME0wSzAJBgUrDgMCGgUABBR+5mrncpqz/PiiIGRsFqEtYHEIXQQUqEpqYwR93brm0Tm3pkVl7/Oo7KECEgRY8NzrWAjZ4J4grl19QqsePQ=
For each alert the last bit of the address changes, but this part is the same:
hxxp://ocsp.int-x3.letsencrypt.org/MFMwUTBPME0wSzAJBgUrDgMCGgUABBR+5mrncpqz/PiiIGRsFqEtYHEIXQQUqEpqYwR93brm0Tm3pkVl7/Oo7KECEg
They all also have a target address of :
104.91.166.211
Just wondering if there is more information on this, what might be causing it, if this is an indicator of a primary infection, etc.