Compatibility issues with Sky router 4.2 and MacBook Air running Big Sur Version 11.1

I have recently had a new Sky Router 4.2 and it is fine on my iPhone 6 running V 12.5.1 and iPad mini 3 running V12.5. But Macbook Air 13 inch running Big Sur V11.1 will not connect to the hub. It recognises the router and shows 3 full signal strength symbols but will not load anything on Safari or Chrome. Also emails will not send. Sometimes the website will load after about 5 minutes or the email eventually will send, but mostly just sits in the outbox.

Sky agent has has run tests and all is fine with the results, and the other 2 Apple devices work fine.

Does anyone have similar problems?