From GoCompare website
Refuse insurance
If you’ve been refused insurance, it means you’ve either had a claim rejected, or your insurer has refused to offer you a renewal quote.
Your insurer might refuse to renew your policy, either because its criteria has changed or they’re no longer able to offer you cover.
But you could also be refused insurance, or refused a renewal because of non-disclosure, leading to your insurance being voided or cancelled.
If you’ve ever had insurance refused you have to declare it when you take out new insurance.
https://www.gocompare.com/car-insurance/guide/declarations-and-non-disclosures/
But a slightly different slant from MSE website..
I tried to get M&S home insurance and was turned down. The operator said that a note had come on her screen to make sure customer understands that this is not a refusal to insure but a decline to quote.
I didn't really understand the difference at the time, but comments on this thread explain it.
https://forums.moneysavingexpert.com/discussion/1312865/what-does-refused-insurance-actually-mean