Perhaps the connection with no Internet was your 5GHz band and when you switched to the other one it connected to 2.4GHz
- Normally when users have separated the bands, they have provided a naming convention like, ‘My wonderful ISP - 2.4GHz’ or ‘My wonderful ISP - 5GHz’
- WiFi devices are notorious for hanging on to a signal, even when it becomes dysfunctional. Band Steering was developed to auto switch to the best available, but the effectiveness of that is still questionable.
- I would suggest making sure your router is at the latest available code level