thanks for reporting the problem, so far we have heard about this from avast/avg users whose security software is meddling with encrypted connections. firefox 61 introduced the better security protocol tls 1.3 & apparently avast can't cope with that yet.

as a workaround, please try to disable the scanning of https connections as described in https://support.mozilla.org/en-US/kb/secure-connection-failed-error-message#w_avast-and-avg-security-products

so i take even if i use this workaround this issue must be solved on avast side not fireforx? or both have to do something? avast developers are aware of this issue?

yes, it's in avast's domain to fix this - they are aware of the problem and promising an update with a fix in the coming days

thanks for the reply

is there a avast page on the issue to keep track of this?

i don't know of any, but since it's not the first time that security software is causing problems in this regard or degrading the connection security in firefox i'd generally recommend to keep that preference turned off.

http://www.cbc.ca/news/technology/antivirus-software-1.3668746 https://blog.vpn.ac/disable-https-scanning.html https://jhalderm.com/pub/papers/interception-ndss17.pdf

ok thanks for the info i will do so

A better solution is just to use Windows Defender, I never recommend AVG or Avast.