Why does Safari crash when accessing scheduled sessions on Coviu after logging in on MacBook Pro?

Safari crashes immediately every time I try and enter my scheduled tele/video sessions on Coviu (after logging successfully into my Coviu account). Clients can access the session links and get admitted (I have tested this). It seems this is not a Coviu issue, but a Safari issue and it is costing me income in sessions that cannot be honoured.

I have recently upgraded to MacOS Sequoia 15.4.1 has this 'reset' or altered parameters on my system - as I have never had this problem in the past year?

[Re-Titled by Moderator]