I figured it out by reading the example source: /** * Root cert for smtp.googlemail.com, taken from server_root_cert.pem * * The PEM file was extracted from the output of this command: * openssl s_client -showcerts -connect smtp.googlemail.com:587 -starttls smtp * * The CA root cert is the last cert...

I am simply trying to run the smtp_client example and I am getting an error which I have not found a solution: 220 2.0.0 Ready to start TLS I (7575) smtp_example: Performing the SSL/TLS handshake... E (8365) smtp_example: mbedtls_ssl_handshake returned -0x2700 E (8365) smtp_example: Last error was: ...