MobileDeviceUpdater - "Can’t download the software because of a network problem."

Hi,

my system specs are:

• OSX - High Sierra - 10.13.6 with latest security update 2020-005
• iPhone SE with iOS 14.0.1

When I connect the phone to my Mac, I got a popup indicating that "A new software update is required to connect to the phone" (below)

This operation never ends successfully because of the message "Can’t download the software because of a network problem."

I've tried different options such as:

• Enable/disable firewall, restart PC, restart phone...
• Install Xcode + Command Line Tools (latest available for High Sierra is 10.1) from the Apple URL https://developer.apple.com/download/more/?&q=xcode

Nothing helped. Nevertheless, after digging for a while, I made one last attempt by directly invoking the MobileDeviceUpdater command from:

$ /System/Library/PrivateFrameworks/MobileDevice.framework/Versions/Current/Resources/MobileDeviceUpdater.app/Contents/MacOS/MobileDeviceUpdater

Which, after some time (again showing up a popup saying "Downloading 1 item") it returned the following log output, which probably provides some more information:

dyld: warning, LC_RPATH @executable_path/../Frameworks in /System/Library/PrivateFrameworks/MobileDevice.framework/Versions/Current/Resources/MobileDeviceUpdater.app/Contents/MacOS/MobileDeviceUpdater being ignored in restricted program because of @executable_path
2020-10-03 15:27:57.044 MobileDeviceUpdater[4783:340981] Software update began.
dyld: warning, LC_RPATH @executable_path/../Frameworks in /System/Library/PrivateFrameworks/MobileDevice.framework/Versions/Current/Resources/MobileDeviceUpdater.app/Contents/MacOS/MobileDeviceUpdater being ignored in restricted program because of @executable_path
dyld: warning, LC_RPATH @executable_path/../Frameworks in /System/Library/PrivateFrameworks/MobileDevice.framework/Versions/Current/Resources/MobileDeviceUpdater.app/Contents/MacOS/MobileDeviceUpdater being ignored in restricted program because of @executable_path
dyld: warning, LC_RPATH @executable_path/../Frameworks in /System/Library/PrivateFrameworks/MobileDevice.framework/Versions/Current/Resources/MobileDeviceUpdater.app/Contents/MacOS/MobileDeviceUpdater being ignored in restricted program because of @executable_path
dyld: warning, LC_RPATH @executable_path/../Frameworks in /System/Library/PrivateFrameworks/MobileDevice.framework/Versions/Current/Resources/MobileDeviceUpdater.app/Contents/MacOS/MobileDeviceUpdater being ignored in restricted program because of @executable_path
2020-10-03 15:28:34.307 MobileDeviceUpdater[4783:340981] Got an error during the update?! Error Domain=SUSoftwareUpdateErrorDomain Code=106 "Can’t download the software because of a network problem." UserInfo={NSLocalizedDescription=Can’t download the software because of a network problem., NSUnderlyingError=0x7ff30d70e3b0 {Error Domain=NSURLErrorDomain Code=-1100 "(null)" UserInfo={NSErrorFailingURLStringKey=https://swdist.apple.com/content/downloads/60/44/001-38529-A_280VD8N1GW/i5lxg0fynfxm4gucy0varw93pb9azg0ii9/001-38529.English.dist, PKURLErrorStatusCode=404, PKURLErrorResponseHeaders={
    Connection = "keep-alive";
    "Content-Length" = 9;
    "Content-Type" = "text/html; charset=iso-8859-1";
    Date = "Sat, 03 Oct 2020 13:27:57 GMT";
    Server = Apache;
}}}}

By looking at the last response, the parameter PKURLErrorStatusCode makes me think that the URL https://swdist.apple.com/content/downloads/60/44/001-38529-A_280VD8N1GW/i5lxg0fynfxm4gucy0varw93pb9azg0ii9/001-38529.English.dist returns a 404 (Not Found).

Pinging the name swdist.apple.com works, so it doesn't seem to be a DNS problem.

Tried the same with the browser (GET request) and also got a 404.

So sadly seems that I cannot make a backup or handle my iPhone/iPad from iTunes anymore?

Do you have any idea what could be the underlying problem (and how to get around it)?

Thanks in advance