iPhone only partially recognized my iMac
I have an iPhone 8+ running iOS 14.4 and an iMac running Catalina 10.15.7. When I plug my phone into my iMac, a window pops up with my phone as its name. There are two buttons: Check for Update, and Restore iPhone. However, the Check for Update is grayed out. In addition, when I open the Music app, my phone shows up in the list of devices, but when I click on it, it says, "The selected device could not be found," which means it doesn't sync.
This has been going on for a while (a few months?), but hasn't always been this way. What can I do to get my Mac to fully recognize my phone?
iPhone 8 Plus