Flashing ESP32 wifi devices over the air(OTA) using node-red?

Thanks for shining some light.
I am using HTTPUpdate example code - just changed the ID and PSWD of my network and URL of ESPhttpUpdate.

I pass the IP of the raspberry PI , port 80 and then the directory where i hold the binary file which is /var/www/html/uploads/dev1.bin
t_httpUpdate_return ret = ESPhttpUpdate.update("192.168.100.158",80, "uploads/dev1.bin");
however, I get this error: