[Philips, Sony, TCL Android TV] BertProesmans:
"Username and password don't match" on itself doesn't provide enough information, it explains an issue occurred between the first and the last step.

Regarding the error "failed to authenticate [..]"; Your TV restarts when you execute the command `adb.exe reboot`, right?

There is a possibility you're connecting to another android device instead. If your TV effectively restarts after executing the command, the error can be ignored.

I can probably debug tonight or tomorrow on the TV of my parents (i'm in CEST) to cross reference Android logs, so I need your TV logs. The information in those logs hopefully details what goes wrong exactly, but can potentially also contains sensitive information about your TV and apps on your TV. It's already an older TV and if you don't use the smart features, the risk of leaking information is low.

Now there are two ways to go about this, export the error-only log, or export a full log from your TV. The full log will show information about everything running on your TV and has a higher chance of containing the cause of the issue(s). To simplify the process and not having to export multiple logs I suggest exporting the full log. If you take issue with exporting potentially sensitive information I suggest to manually inspect the log data and replace anything you find suspicious with the text `[REDACTED]`.

To export Android TV logs, do the following;

ON YOUR COMPUTER - Setup adb and collect logs

1. Connect to your tv with adb, exactly like the install instructions from earlier post

2. *Instead of installing*, execute adb.exe logcat > logcat.txt

-- To only export errors, execute adb.exe logcat *:E > logcat_err.txt

-- The program will execute but produce no output, it is running and capturing logs from your TV

ON YOUR TV - Try logging in

3. Attempt to login with app passwords

4. Note the time in your local timezone

-- This is important to correlate log data with your actions on the TV

ON YOUR COMPUTER - Finish log collection and upload

5. In the command window, press the keyboard shortcut [CONTROL] + [C]

-- This will stop the running program `adb.exe logcat`

-- In the folder where your `adb.exe` file exists, there should be a new text-file with name `logcat`

6. Open the text file `logcat`, the file must contain a bunch of dates and text

-- If the textfile `logcat` is empty or you get an error on opening, close the text-file, then close the cmd.exe window, then reopen the text file

ON YOUR COMPUTER - Upload the log file to this thread

7. Create a reply post in this forum thread

8. Put the time your noted in step 4 in the reply post

-- This time is required to filter down the text to when you tried logging in on your TV

9. Click the "Attach files" button (to the left side of the button "Post reply"), and select the text file `logcat`

-- This uploads the text file as attachment to your new post

10. Post your reply

DONE

Why attach the logcat text file to a post in this thread? My Android experience is on the hobbyist level, I cannot guarantee I'll be able to solve the issue with your TV. More people who can take a look at your log file means a higher chance of someone being able to point out and/or solve the issue with your TV.