windows 10 Pro 21 H2 Kaspersky Internet Security 21.3.10.391 My problem seemed initially to be the same as "Secure traffic in Microsoft Windows...is not monitored” I have 5 KAV certificates. Why, and which one do I use with Mozilla apps?". There were warnings in the KIS interface which I couldn’t get rid of despite following the advice about exporting the Kaspersky trusted certificate and entering it into Mozilla Firefox and Thunderbird storage, which I did. I followed Schulz's advice re changing the store used within KIS and opening and closing Thunderbird. I also reconfigured Thunderbird and Firefox to use the system’d certificate storage. This worked partially in that the error messages within the KIS interface disappeared, but Thunderbird is still being blocked from connecting to the Virgin Media server and cannot pick up or send messages via Virgin's servers. Can someone help please?