Today it came to my attention that in newer versions of Chrome and Mozilla, StartCom was removed from the browsers trusted CAs due to WoSign (purchaser of StartCom) doing dubious actions and bussness activities (e.g. unauthorized certificate issuance). I couldn't notice before because apparently only certificates issued after 21st October 2016 were distrusted previously.
I perhaps switched all of the web infrastructures using Apache to Let's Encrypt, I couldn't however switch anything which involves XMPP/Metronome web bits directly due to the poor support of the ACME's protocol of multi-machine environments, and using the provided dns authentication results complicated due to caching.
This means that you may get SSL errors with the E-Mail verification OR Password Reset for accounts, or when using Jappix for the time being.