40103: Basic authentication used over an insecure connection

Basic authentication was attempted over a connection that was not secured with TLS. Basic authentication sends the API key directly, so it is only permitted over an encrypted transport.

What you should do

Either use Basic authentication over a TLS connection, or switch to token authentication if you need to connect without TLS. SDKs use TLS by default, so this normally means TLS was explicitly disabled in the client options.

Why it happens

A client authenticated with an API key (Basic authentication) over a connection that wasn't secured with TLS. Because the key would be exposed to anything inspecting the unencrypted traffic, the request is rejected rather than risk the long-lived credential.

What you'll see

The error is reported with code 40103 and HTTP status 401. The message is Invalid use of Basic authentication over non-TLS transport.