problems include slow response, no response, unable to receive calls, unable to make calls, and a variety of other less critical issues. Phone worked fine before 17.1.1, so that suggests the cause is in IOS 17.1.1.
The temporary fix seems to be to turn the iPhone off and back on to clear the errors…just like the old days of MS Windows.
iPhone 11, iOS 17
If turning the iPhone off and back on provides a temporary fix, I suggest that you restore the device to factory, then restore your backup. Restoring to factory will download and install a fresh version of the iOS. It is possible there is a problem there that should be corrected with a fresh iOS download and install. Restore your iPhone, iPad, or iPod to factory settings - Apple Support then Restore your iPhone, iPad, or iPod touch from a backup - Apple Support
Did try to force restart it or better to reset the iPhone as a new phone?
iOS 17.1.1 issues on iPhone11
