This used to work nicely. I can connect this phone to other Macs. Also I can connect other phones to this Mac. Just these two don't want to get along in the Finder.

This used to work nicely. I did however restore this phone from a backup.

I can connect this phone to other Macs. Also I can connect other phones to this Mac. Just these two don't want to get along in the Finder.

already gives me a Operation not permitted even though the terminal has "full disk access" permissions.

AMPDeviceDiscoveryAgent AMDeviceStartSession failed (0xE8000003) for device 0x7fcf0390820

nehelper    -[NWPrivilegedHelper startXPCListener]_block_invoke client pid 204 does not have any known entitlement
configd networkd_privileged_check_interface_settings_block_invoke received XPC_ERROR_CONNECTION_INVALID

AMPDeviceDiscoveryAgent AMDeviceCopyValueWithError failed (0xE8000016) for device 0x7fcf0390820
kernel  Sandbox: AMPDeviceDiscove(570) deny(1) mach-lookup com.apple.softwareupdated

already gives me a Operation not permitted even though the terminal has "full disk access" permissions. (When I temporarily disabled the system integrity protection via csrutil disable in the recovery console, I found that this folder is empty anyway.)

AMPDeviceDiscoveryAgent AMDeviceStartSession failed (0xE8000003) for device 0x7fcf0390820

nehelper    -[NWPrivilegedHelper startXPCListener]_block_invoke client pid 204 does not have any known entitlement
configd networkd_privileged_check_interface_settings_block_invoke received XPC_ERROR_CONNECTION_INVALID

AMPDeviceDiscoveryAgent AMDeviceCopyValueWithError failed (0xE8000016) for device 0x7fcf0390820
kernel  Sandbox: AMPDeviceDiscove(570) deny(1) mach-lookup com.apple.softwareupdated

Update 3:

When Xcode tries to connect with the iPhone, it fails and shows this in the details:

Failed to enable wireless functionality on the device.
Domain: com.apple.dtdevicekit
Code: 805
Recovery Suggestion: Please check the device connection and ensure that a passcode is set on the device.
User Info: {
    AssociatedMobileDeviceFunction = DTDKEnableWireless;
    DVTRadarComponentKey = 487927;
}
--
Could not allocate a resource.
Domain: com.apple.dt.MobileDeviceErrorDomain
Code: -402653181
User Info: {
    DVTRadarComponentKey = 261622;
    MobileDeviceErrorCode = "(0xE8000003)";
    "com.apple.dtdevicekit.stacktrace" = (
    0   DTDeviceKitBase                     0x0000000121dd093f DTDKCreateNSErrorFromAMDErrorCode + 220
    1   DTDeviceKitBase                     0x0000000121e09643 __39-[DTDKMobileDeviceToken enableWireless]_block_invoke_3 + 200
    2   DVTFoundation                       0x000000010510e29a __DVT_CALLING_CLIENT_BLOCK__ + 7
    3   DVTFoundation                       0x000000010510febc __DVTDispatchAsync_block_invoke + 1191
    4   libdispatch.dylib                   0x00007fff6fba56c4 _dispatch_call_block_and_release + 12
    5   libdispatch.dylib                   0x00007fff6fba6658 _dispatch_client_callout + 8
    6   libdispatch.dylib                   0x00007fff6fba8818 _dispatch_continuation_pop + 414
    7   libdispatch.dylib                   0x00007fff6fba7f16 _dispatch_async_redirect_invoke + 703
    8   libdispatch.dylib                   0x00007fff6fbb4957 _dispatch_root_queue_drain + 326
    9   libdispatch.dylib                   0x00007fff6fbb5097 _dispatch_worker_thread2 + 92
    10  libsystem_pthread.dylib             0x00007fff6fe009f7 _pthread_wqthread + 220
    11  libsystem_pthread.dylib             0x00007fff6fdffb77 start_wqthread + 15
);
}
--


System Information

macOS Version 10.15.7 (Build 19H2)
Xcode 12.1 (17222)

When I connect my iPhone SE to my MacBook (Catalina 10.15.7) and open the Finder tab for the iPhone I am asked whether the Computer should trust this phone. When I click the button "Trust" I get the error:

Trust request error 0xE8000003

No connection is made.

This used to work nicely. I can connect this phone to other Macs. Also I can connect other phones to this Mac. Just these two don't want to get along in the Finder.

Btw, I can use the "Image Capture" app just fine!

How can I fix this?

Update:

There is this uncommented solution in the Apple forums, but running the first command:

sudo rm -rf /private/var/db/lockdown

already gives me a Operation not permitted even though the terminal has "full disk access" permissions.

When I connect my iPhone SE to my MacBook (Catalina 10.15.7) and open the Finder tab for the iPhone I am asked whether the Computer should trust this phone. When I click the button "Trust" I get the error:

Trust request error 0xE8000003

No connection is made.

This used to work nicely. I can connect this phone to other Macs. Also I can connect other phones to this Mac. Just these two don't want to get along in the Finder.

Btw, I can use the "Image Capture" app just fine!

How can I fix this?

Update:

There is this uncommented solution in the Apple forums, but running the first command:

sudo rm -rf /private/var/db/lockdown

already gives me a Operation not permitted even though the terminal has "full disk access" permissions.

Update 2:

I see the following - maybe related - console errors when pressing the "Trust" button:

AMPDeviceDiscoveryAgent AMDeviceStartSession failed (0xE8000003) for device 0x7fcf0390820

nehelper    -[NWPrivilegedHelper startXPCListener]_block_invoke client pid 204 does not have any known entitlement
configd networkd_privileged_check_interface_settings_block_invoke received XPC_ERROR_CONNECTION_INVALID

AMPDeviceDiscoveryAgent AMDeviceCopyValueWithError failed (0xE8000016) for device 0x7fcf0390820
kernel  Sandbox: AMPDeviceDiscove(570) deny(1) mach-lookup com.apple.softwareupdated