To authenticate to the Assembly Payments API, there are two methods to use:
- Basic authentication using your username and API key.
- Tokenised authentication using a Base64 encoded username and API key to pass a single authentication token.
For more information on API keys and authenticating with Assembly Payments, refer to the Generating API Keys guide.
The error "token not authorised" might indicate that you're passing just the API key for tokenised authentication and not an encoded username+API key combination.