If there are problems on the Access Journey through the Captive Portal Splash Pages with Instagram, or Twitter not loading and CSS (the appropriate page styling from that Social Media site) this is likely to be it falling over on a simultaneous SLL based call for data from this site.
To 'allow' this you'd need to make an adjustment to the Winbox RouterOS set up; you will have (as well the the Wall Garden list) the Wall Garden IP list
Might you please try adding the Twitter (and Instagram, if you plan to use it) domains in the Wall Garden IP List as well?
On Wall Garden IP List, add all the below entries once at a time by clicking the "+" button.
- Action: Allow
- Server: This should be the MAC address you entered before
- Dst. Host: *.twimg.com
- Action: Allow
- Server: This should be the MAC address you entered before
- Dst. Host: api.twitter.com
- Action: Allow
- Server: This should be the MAC address you entered before
- Dst. Host: instagram.com
- Action: Allow
- Server: This should be the MAC address you entered before
- Dst. Host: api.instagram.com
