It looks like there is a connectivity issue for some users today posting data to emoncms.org from I think mostly emonpi/emonbase systems starting 3pm onwards. It’s affecting about 10% of emoncms.org feeds.
This may be related to a now expired letsencrypt certificate Help thread for DST Root CA X3 expiration (September 2021) - Help - Let's Encrypt Community Support.
If you have an affected system and can post any emonhub logs that may show associated errors that would be really useful. I will hopefully get a clearer idea of the solution shortly.
It may require running: sudo apt-get update && sudo apt-get upgrade to pull in latest certificates.