Just the change to WiFiSecureClient didn't work once some debugging values were set back to a real value. However, I did figure out that I had the HTTPClient as a global, instead of a local variable. This appears to be the key, since following Basic HTTPS Client example pattern works fine in my code...

Looks like moving from WiFiClient to WiFiSecureClient, and adding in the Cert/Key seems to fix the error.

Found a demo here: https://github.com/espressif/arduino-es ... Secure.ino

I have an Olimex ESP32-EVB board with several sensors talking to a webserver. The first time through, the board sends the data fine: connecting to 172.16.0.172 - connected to: https://172.16.0.172/api/device/update {"device_uuid":"692cc64f-c824-4d11-9252-b824f2dd18c4","last_mac":"BC:DD:C2:F1:72:F8",...