This may happen when the hotspot/access point is redirecting to a page to accept terms and conditions, or when an intermediary is intercepting your browsing.

For the first issue, try an unsecure address first, such as http://example.com/ and complete any required authentication process. Do secure addresses work after that?

For the second issue, does the error page provide any access to certificate details, such as a view certificate link/button?

Thank you. I had to insist on another page. Solved!