Macbook Pro can’t connect to public wifi please help

How about simply uninstalling Sophos?

Looks like it was a Sophos problem for me. You can either uninstall Sophos or check out the work around below.

https://support.home.sophos.com/hc/en-us/articles/360020126572-Captive-Portal-Login-Page-does-not-load-on-MacOS-when-connecting-to-a-Public-Guest-Wi-Fi-Hotspot-

Uninstalling was already suggested, but for some corporate users, may not be an option. Some of the other workarounds in the referenced Sophos link are kind of difficult for some users. They might be able to get away with turning off the Web Protection piece (which causes the problem) if uninstalling isn’t allowed.

The IT staff at that organization needs training.

Uninstalling was already suggested, but for some corporate users, may not be an option. Some of the other workarounds in the referenced Sophos link are kind of difficult for some users. They might be able to get away with turning off the Web Protection piece (which causes the problem) if uninstalling isn’t allowed.

Some routers aren't friendly with all browsers for connectivity. Try either Firefox or Chrome to see if they connect.

java.com will ensure your Java is up to date.

This is also happening to me ever since I upgraded to Mojave.

You can also temporarily disable Sophos Web Protection until you get past the splash screen to get on to the WiFi.

Launch Sophos Anti-Virus (the application). Go to Preferences->Web Protection and under the General tab, turn "Block access..." until you get on to the WiFi, then re-enable it.

My point was that it is not necessary and most AV apps play havoc with mac OS. As well, if I was working in a corporate environment where someone demanded that I install such an app, I would find another place to work. Fortunately, I am not. My financial institution demanded that I install one to access my account on their website, so I changed banks.