As of Oct 1st the way Let's encrypt certs work have changed. For those using 3CX FQDNs this could mean that you'll start seeing DST root cert expiry errors on older browsers or some Mac OS devices.
DST Root CA X3 Expiration (September 2021)
The issue with certs seem to mainly hit Mac OS users. In most cases if you see he issue you should be able to resolve by clearing your cache or restarting the device.
For those still affected there are workarounds out there to manually install the cert but I couldn't recommend an option here. Rather, it would be better to update your OS if possible as this will automatically set up the required ISRG X1 Root CA trust..
DST Root CA X3 Expiration (September 2021)
The issue with certs seem to mainly hit Mac OS users. In most cases if you see he issue you should be able to resolve by clearing your cache or restarting the device.
For those still affected there are workarounds out there to manually install the cert but I couldn't recommend an option here. Rather, it would be better to update your OS if possible as this will automatically set up the required ISRG X1 Root CA trust..
