My wifi connection keeps cutting out and the website page keeps spinning. Hardwired internet seems to be working fine.

One AP is on ground floor and the other on second floor. They both have the same SSID and are running 2.4ghz and 5ghz concurrently.

Any ideas?

Check the channel cross modulation (congestions), using a wifi tool, with an Adroid phone for portability as an example.

If there is a lot of traffic, make sure everything is wound down to HT20, and uses the least congested channel. 5Ghz is growing now, and a lot of companies like talktalk use HT80 for the 5GHz and this can cause issues too.