Error encountered when adding yum repos to a product while behind a corp firewall

Problem:
I’ve got a fresh install on CentOS 7 of Foreman/Katello, and when I add a new yum repo to download I get the following error:
‘’’ An error occurred saving the Repository: Task e4b860a9-ef54-427d-9f97-e34b5f2d54cd: PulpRpmClient::ApiError: Error message: the server returns an error HTTP status code: 400 Response headers: {“date”=>“Mon, 03 May 2021 19:40:46 GMT”, “server”=>“gunicorn/20.0.4”, “content-type”=>“application/json”, “vary”=>“Accept,Cookie”, “allow”=>“GET, PUT, PATCH, DELETE, HEAD, OPTIONS”, “x-frame-options”=>“SAMEORIGIN”, “content-length”=>“56”, “correlation-id”=>“3f10ae10-6261-49e7-a1ae-5a5ab4542b1e”, “access-control-expose-headers”=>“Correlation-ID”, “via”=>“1.1 repomirror.example.com”, “connection”=>“close”} Response body: {“proxy_url”:[“proxy_url must not contain credentials”]}
‘’’

I’ve set up the proxy under Infrastructure / HTTP Proxy. My company’s web proxy requires userid/password authentication to be used. I’ve got that set in the proxy page, and the test works. However I get the error thrown as a popup when I add a repo using the configured proxy. If I remove the userid/password from the proxy, I get a different error, which I expect as the company web proxy requires authentication.

Expected outcome:
Repository to begin to sync

Foreman and Proxy versions:
Version 2.5.0-develop © 2009-2021 Paul Kelly and [Ohad Levy]

Foreman and Proxy plugin versions:
foreman-tasks 4.1.0
foreman_remote_execution 4.3.0
katello 4.1.0.pre.master

Distribution and version:
CentOS Linux release 7.9.2009 (Core)

Other relevant data: