El Capitan Apple Mail.app Passwords Won't Take

Hosting provider had a security breach and didn't tell me. Passwords reset, all is good.

Cheers

Found a mail log:

Sep  1 07:57:15  Mail[1757] <Debug>: <0x7fafcc6f09c0:[Disconnected]> Read: * OK [CAPABILITY (
	    IMAP4REV1,
	    STARTTLS,
	    "AUTH=PLAIN",
	    "AUTH=LOGIN"
	)]
Sep  1 07:57:15  Mail[1757] <Debug>: <0x7fafcc6f09c0:[Non-authenticated]> Wrote: 1.32 STARTTLS
Sep  1 07:57:15  Mail[1757] <Debug>: <0x7fafcc6f09c0:[Non-authenticated]> Read: 1.32 OK
Sep  1 07:57:16  Mail[1757] <Debug>: <0x7fafcc6f09c0:[Non-authenticated]> Wrote: 2.32 CAPABILITY
Sep  1 07:57:16  Mail[1757] <Debug>: <0x7fafcc6f09c0:[Non-authenticated]> Read: * CAPABILITY IMAP4REV1 AUTH=PLAIN AUTH=LOGIN
Sep  1 07:57:16  Mail[1757] <Debug>: <0x7fafcc6f09c0:[Non-authenticated]> Read: 2.32 OK
Sep  1 07:57:16  Mail[1757] <Debug>: <0x7fafcc6f09c0:[Non-authenticated]> Wrote: 3.32 AUTHENTICATE PLAIN
Sep  1 07:57:16  Mail[1757] <Debug>: <0x7fafcc6f09c0:[Non-authenticated]> Read: +
Sep  1 07:57:16  Mail[1757] <Debug>: <0x7fafcc6f09c0:[Non-authenticated]> Read: 3.32 BAD Authentication aborted by client.
Sep  1 07:57:16  Mail[1757] <Debug>: <0x7fafcc6f09c0:[Non-authenticated]> Wrote: 4.32 AUTHENTICATE PLAIN
Sep  1 07:57:16  Mail[1757] <Debug>: <0x7fafcc6f09c0:[Non-authenticated]> Read: +
Sep  1 07:57:16  Mail[1757] <Debug>: <0x7fafcc6f09c0:[Non-authenticated]> Read: 4.32 BAD Authentication aborted by client.
Sep  1 07:57:16  Mail[1757] <Debug>: <0x7fafcc6f09c0:[Non-authenticated]> Wrote: 5.32 AUTHENTICATE LOGIN
Sep  1 07:57:16  Mail[1757] <Debug>: <0x7fafcc6f09c0:[Non-authenticated]> Read: +
Sep  1 07:57:16  Mail[1757] <Debug>: <0x7fafcc6f09c0:[Non-authenticated]> Read: 5.32 BAD Authentication aborted by client.
Sep  1 07:57:16  Mail[1757] <Debug>: <0x7fafcc6f09c0:[Non-authenticated]> Wrote: 6.32 AUTHENTICATE LOGIN
Sep  1 07:57:16  Mail[1757] <Debug>: <0x7fafcc6f09c0:[Non-authenticated]> Read: +
Sep  1 07:57:16  Mail[1757] <Debug>: <0x7fafcc6f09c0:[Non-authenticated]> Read: 6.32 BAD Authentication aborted by client.
Sep  1 07:57:16  Mail[1757] <Debug>: <0x7fafcc6f09c0:[Non-authenticated]> Wrote: 7.32 LOGOUT

Seems this fine application (whose rules never work) can't even authenticate. The account is just fine.

Actually, it's not working. Accounts keep refusing the passwords.

I've got Mail.app closed and into System Preferences::Internet Accounts and I just deleted my account, and re-created it. It still says Unable to verify account name or password.

Now what should I do?

Cheers

Just deleted the full account, both in Mail.app and System Preferences::Internet Accounts.

Started fresh. SP::IA tried with my account info and it still says "Unable to verify account name or password." Webmail works. Nothing has changed.

Why is OSX not working? Console on internetaccounts:

2020-09-01 7:32:04.815 AM com.apple.preferences.internetaccounts.remoteservice[889]: Unable to simultaneously satisfy constraints:
(
    "<NSLayoutConstraint:0x7ff18dca9850 H:[NSView:0x7ff18dc1bc60(405)]>",
    "<NSLayoutConstraint:0x7ff18b7153f0 H:|-(0)-[NSView:0x7ff18dc1bc60]   (Names: '|':NSView:0x7ff18dc01b30 )>",
    "<NSLayoutConstraint:0x7ff18dc28870 H:[NSView:0x7ff18dc1bc60]-(0)-|   (Names: '|':NSView:0x7ff18dc01b30 )>",
    "<NSLayoutConstraint:0x7ff18dcaff20 H:[NSView:0x7ff18dc01b30(407)]>"
)

Will attempt to recover by breaking constraint 
<NSLayoutConstraint:0x7ff18dca9850 H:[NSView:0x7ff18dc1bc60(405)]>

Set the NSUserDefault NSConstraintBasedLayoutVisualizeMutuallyExclusiveConstraints to YES to have -[NSWindow visualizeConstraints:] automatically called when this happens.  And/or, break on objc_exception_throw to catch this in the debugger.
2020-09-01 7:32:04.816 AM com.apple.preferences.internetaccounts.remoteservice[889]: Unable to simultaneously satisfy constraints:
(
    "<NSLayoutConstraint:0x7ff18dc45960 V:[NSView:0x7ff18dc1bc60(197)]>",
    "<NSLayoutConstraint:0x7ff18dc30090 V:|-(0)-[NSView:0x7ff18dc1bc60]   (Names: '|':NSView:0x7ff18dc01b30 )>",
    "<NSLayoutConstraint:0x7ff18dc1d500 V:[NSView:0x7ff18dc1bc60]-(0)-|   (Names: '|':NSView:0x7ff18dc01b30 )>",
    "<NSLayoutConstraint:0x7ff18dcab510 V:[NSView:0x7ff18dc01b30(301)]>"
)

Will attempt to recover by breaking constraint 
<NSLayoutConstraint:0x7ff18dc45960 V:[NSView:0x7ff18dc1bc60(197)]>

Set the NSUserDefault NSConstraintBasedLayoutVisualizeMutuallyExclusiveConstraints to YES to have -[NSWindow visualizeConstraints:] automatically called when this happens.  And/or, break on objc_exception_throw to catch this in the debugger.
2020-09-01 7:32:08.495 AM com.apple.preferences.internetaccounts.remoteservice[889]: Error in CoreDragRemoveTrackingHandler: -1856
2020-09-01 7:32:08.495 AM com.apple.preferences.internetaccounts.remoteservice[889]: Error in CoreDragRemoveReceiveHandler: -1856


Actually everything is working now. Multiple restarts and placing passwords in System Preferences::Internet Accounts as well as Mail.app::Preferences::Accounts eventually worked.

Cheers