"Wi-Fi has no internet access"

If you’re connecting your Android phone to a network and find that everything else connects to that network fine except your phone and you get the above error, this could be the fix. <IMG SRC=https://user-images.githubusercontent.com/7669921/136776940-3c068854-9be0-4934-9c9d-b80fbe07b314.png>

You've already tried * Rebooting * Resetting Network Settings * Factory Reset (really?) * Connecting to another WiFi network * Other stuff that XDA forums, Tom's Hardware etc. recommend The one that I didn't see on any searches was "Set your Date & Time" correctly.
I was resetting a phone to sell on ebay. It hadn't been powered on for a while, and the clock was out by 3 years. As it had no SIM card in, it couldn't get the time automatically from the Mobile Network provider.
As soon as the time was set correctly then I could access web pages. To remove the warning of "has no internet access" I had to reconnect to the wifi network after fixing the time. Hope that saves someone else