[BlueOnyx:22435] LetsEncrypt Automatic Renewals

[Colin Jack]

Not sure what is happening but al LE auto renewals have stopped working on multiple servers.
Had a shed load of these through in the last few days:

Let's Encrypt certificate expiration notice for domain "domain.com" (and 1 more)
Your certificate (or certificates) for the names listed below will expire in 19 days (on 31 Oct 18 16:10 +0000). Please make sure to renew your certificate before then, or visitors to your website will encounter errors.

All are set to auto renew and have done in the past.
Manual renewal works fine. So just the auto renew seems to have stopped working.

Anybody any ideas why?

Thanks

Colin