The string is on SDcard, so thats not an issue.
pylon:
I don't see why you cannot connect to the ESP32, as the root certificate is used for making a request from the ESP32 to an HTTPS server. So the ESP32 cannot connect to the outside world (by HTTPS) but not the other way around.
Good point. I had an ESP who didn't respond anymore, so I did not look any further to see if there might be a one way direction left. I'll try that!
pylon:
BTW: Are you sure your hoster replaces the root certificate and not some intermediate certificate?
That's what my ISP told me, and the certificate has changed indeed.