Need help authenticating against the testo Saveris Data API (and testo Saveris Device API)

[dorothy-hawley]

using the instructions in this document here https://developers.testo.dev/saveris-logger-api/general/security/#authentication we are trying to connect to the API but the response is 400 Bad Request

{
"Status": "Error",
"Message": "Incorrect username or password."
}

at this page: https://www.eu.saveris.testo.com/stationary-monitoring/overview

I can log into our account and see the device attached to the account.

What credentials should I be using? -- the credentials that give me access to the stationary-monitoring do not work for accessing the API.