Https vs http js integration problem with collect.chat [solved, not grav, remove me]

Hi

I have configured my chatbot (assistant) using https://collect.chat/.

It works when I use http, however when I switch to https (using grav builtin switch in admin panel) the widget with the chatbot doesn't appear.

I've checked in by browser developer's tools (network tab) and confirmed I have no http in https problems (all traffic, all scripts and requests are https). No reported problems with certificates. All should load smoothly.

I also don't see any new, additional problems related to switching to https from http.

Switching http to https just causes the widget to stop appearing. It is present in the source code but it doesn't show up.

I also tried to switch to secure cookie (https + secure cookie). Same results, no luck.

I've contacted collect.chat too, but maybe it's on the grav's side?

Could you help me to debug it? Where should I look?

Does switching http to https imply any additional settings I should be aware of?

Thanks!
Alex

PS
Version: up to date as for today v 1.5.6.

I've isolated this problem. It's not grav. Please remove the topic (I don't have sufficient rights).

I've placed the code in pure html and the same issue is present.

Thanks!