Web-to-Lead no data transfer

[Harald]

I'm trying to transfer data. In postman I get status 200 so okay.
The data is transferred but In the logs I find an error message which is confusing.

Espo.ERROR: CronManager: Failed job running, job [5d3f03f21acee70ed]. Error Details: 5.7.8 Error: authentication failed: UGFzc3dvcmQ6 [] []