I just downloaded the latest Charles 4.6.5 and used it on my simulator, try to download the Charles certificate and noticed it expired at 25 Sep 2023.
I tried downloading from https://chls.ssl/pro, also shown as expired.
Used openssl x509 -enddate -noout -in charles-proxy-ssl-proxying-certificate.pem to check it
Is there no newer certificate available?
To get the updated certificate, go to
Charles -> Help -> SSL Proxying -> Reset Charles Root Certificate
Remove the existing iOS Certificate Profile
Setting -> General -> VPN & Device Mgmt -> The Cert, and remove it,
Then reinstall it using https://chls.pro/ssl
A detail guide from https://charlesdocsy.com/2021/12/29/expired-charles-proxy-root-certificate/
After that, restart your Charles and Simulator if it is still not working.