State Farm denied my claim bcuz my boyfriend was driving. (CT) Can I win an appeal?

My boyfriend and I live together and he had his vehicle on my policy until a few weeks ago when his engine blew and we’re looking for a new car for him. On 12/24/24, he drove my Jeep to work and backed into a truck and the window shattered and lift gate damaged. I haven’t had any tickets or claims in over 10 years, thank God! I’ve also been insured with them since I was 16 so I’m furious! I’m in Connecticut and he had permission. The denial letter stated “we have investigated your claim and found that our insurer is not legally liable for the damages.” I’m obviously going to appeal. Has this happened to anyone else and did you successfully overturn their decision? I have full coverage and the bill still comes in both our names if that helps. Thanks.