I would either contact your partner or Aruba Support to walk through the steps.
If you want to resolve it yourself, my first rescue tool is the developer tools in the browser. I use Firefox the most, but I know it is also available in Chrome and I think even in Edge and other browsers. In the developer tools, you can see in the Network tab what requests your browser is doing, and who or what is responding with what redirect or response. First find out what part of the process is broken, and work step by step through to a solution.
This page contains an overview of the most common issues that people have with guest captive portal.
Also, I created some time ago
this video to explain the guest process step-by-step and how to monitor/troubleshoot it.
Please be advised that not changing the certificate to a valid public trusted one, can result in all kinds of unexpected issues. It may even be that if you add a trusted certificate it suddenly starts to work. Depending on the client operating system, it may even block posting the credentials to prevent them from leaking out, so you may be chasing ghosts without a good certificate.
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Herman Robers
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If you have urgent issues, always contact your Aruba partner, distributor or Aruba TAC Support. Check
https://www.arubanetworks.com/support-services/contact-support/ for how to contact Aruba TAC.
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