I’m at an actual loss. Because it occurs timemachinig to an exterior drive HFS drive (related to a Mac Mini M2) used to work no points.
I’ve additionally tried with an APFS simply because.
Did all of the dances I might discover (going as much as web page three in google searches), overlook the drive, clear the associated keychain keys, reconnect, reboots and many others. No luck.

The factor all the time ends, after a couple of seconds, with

The community backup disk couldn’t be accessed as a result of there was a
drawback with the community username or password. Chances are you’ll must
re-select the backup disk and enter the proper username and
password.

Which taken along with

backupd: (TimeMachine) [com.apple.TimeMachine:General] Authentication
error (80) – the proper person or password data could not exist within the
System.keychain or the server could not enable entry for this
person.

Appears to level to a keychain situation, since in fact the corresponding keychain document exists.

An previous submit [https://arstechnica.com/civis/threads/keychain-issues.1225417/] gave me some hope, however the options recommended there didn’t work, as my plists don’t seem defective.

I can entry it & handle its content material no points, in addition to (as soon as mounted) choose it as TM goal. TM can’t discover it when making an attempt to backup to it.

Additionally, I checked ../Preferences/apple.com.safety.plist (each my person’s and world) in opposition to a TM backup of some days in the past. No variations 🙁

Moreover, I put in a clear Ventura, similar because the one working on the affected machine, on an exterior T3. Booted from it, did the TM settings dance to the community exterior drive… and naturally issues work.
In search of variations, I seen that within the clear Ventura /Library/Preferences/apple.com.safety.plist doesn’t exist. Nor it’s created upon reboot.
So I deleted the one on the affected machine. TM nonetheless fails.
Rebooted. TM nonetheless fails.

Following @KhaineBOT recommendation, I checked the console for NetSysAuthAgent occasions on the affected machine. It clearly present the steps to failure, as follows:

Creating MechType session for stage 0
NetAuthSysAgent Mount URL: request D3389FED-52D6-4CA1-A11E-D4783431B91A from backupd (546)
NetAuthSysAgent URL = smb://mini@MiniM2.native./256GBAPFS
NetAuthSysAgent Session created
NetAuthSysAgent GetServerInfo serverParamsDict = {
GuestOnly = 0;
MechTypesSupported = {
SPNEGONegTokenInitHintsHostname = "not_defined_in_RFC4178@please_ignore";
SPNEGONegTokenInitMechs = {
"1.2.752.43.14.3" = {size = 0, bytes = 0x};
"1.2.840.113554.1.2.2" = {size = 0, bytes = 0x};
"1.2.840.48018.1.2.2" = {size = 0, bytes = 0x};
"1.3.5.1.5.2.7" = {size = 0, bytes = 0x};
"1.3.6.1.4.1.311.2.2.10" = {size = 0, bytes = 0x};
"1.3.6.1.5.2.5" = {size = 0, bytes = 0x};
"1.3.6.1.5.5.14" = {size = 0, bytes = 0x};
};
SPNEGOServerSupportsLKDC = sure;
};
SMBNativeOS = WINDOWS;
ServerDisplayName = "MiniM2.native.";
SupportsChangePassword = 0;
SupportsGuest = 1;
}
NetAuthSysAgent SecKeychainSetUserInteractionAllowed(false) secKeychainStatus = 0
NetAuthSysAgent Discovered Server Marker for "MiniM2.native."
NetAuthSysAgent SecKeychainSetUserInteractionAllowed(interactionAllowed) secKeychainStatus = 0
NetAuthSysAgent Person has visited this machine earlier than
NetAuthSysAgent isKnownServer 1
NetAuthSysAgent Subsequent CredentialsStage set to 1
NetAuthSysAgent Subsequent CredentialsStage set to 2
NetAuthSysAgent Creating MechType session for stage 2
NetAuthSysAgent Including the person identify "mini" to the MechType session data
NetAuthSysAgent NAHCreate: hostname=<non-public> service=cifs
NetAuthSysAgent NAHCreate: will use hostname=<non-public>
NetAuthSysAgent NAHCreate: will use service=cifs
NetAuthSysAgent NAH: particular identify is: <non-public> foo
NetAuthSysAgent NAHCreate: username=<non-public> username given
NetAuthSysAgent NAHCreate: SPNEGO hints identify <non-public>
NetAuthSysAgent NAHCreate-krb: have_kerberos=sure try_iakerb_with_lkdc=no try-wkdc=sure use-spnego=sure
NetAuthSysAgent MechType session created for host "MiniM2.native.", service "cifs".
NetAuthSysAgent Unable to get a MechTypes for the MechType session utilizing credentials

… repeats above in 5 levels, and offers up

NetAuthSysAgent There aren't any MechTypes out there for the MechType session
NetAuthSysAgent Calling OpenSession:
NetAuthSysAgent server smb://mini@MiniM2.native./256GBAPFS
NetAuthSysAgent OpenSession failed 80
NetAuthSysAgent CloseSession outcome 0
NetAuthSysAgent Reply Connect with Server standing = 80

…TM backup failed

Any concepts, pointers will probably be vastly appreciated.