Maybe this will help some people-- I found this crucial step was not immediately evident for the reinstall of the new connect app:  Notifications needs to be toggled ON, access in YOUR phone Settings>Bluetooth > (Device) Connected> tap on the circled i to access the toggle.  HTH
I have an Iphone 11 Pro Max, with a Dell Inspiron 15 5000 Series -5593 ... Dell Mobile Connect keeps reporting the error below, even though I do not turn bluetooth off. All drivers and apps have been updated on both the laptop and the Iphone... The laptop is basically brand new... The error keeps recurring after multiple reboots. [IMAGE]    
Dell Mobile Connect Bluetooth Connection Failure