Did Garmin change authentication API?

[llalundo]

I am not an expert. But it seems that very recently (less than a day) something on Garmin's side changed. My scripts using package garminconnect all broke. Login not possible anymore.

Login failed: 401 Client Error: Unauthorized for url: https://connectapi.garmin.com/oauth-service/oauth/preauthorized?ticket=ST-0273168-icMNbOhcDmJToAzDdOvm-cas&login-url=https://sso.garmin.com/sso/embed&accepts-mfa-tokens=true (status=401)
Traceback (most recent call last):
File "/Users/mimamu/myPython/garminweb_mimamu/venv/lib/python3.14/site-packages/garminconnect/init.py", line 498, in login
token1, token2 = self.garth.login(
~~~~~~~~~~~~~~~~^
self.username,
^^^^^^^^^^^^^^
self.password,
^^^^^^^^^^^^^^
prompt_mfa=self.prompt_mfa,
^^^^^^^^^^^^^^^^^^^^^^^^^^^
)
^
File "/Users/mimamu/myPython/garminweb_mimamu/venv/lib/python3.14/site-packages/garth/http.py", line 167, in login
self.oauth1_token, self.oauth2_token = sso.login(
~~~~~~~~~^
*args, **kwargs, client=self
^^^^^^^^^^^^^^^^^^^^^^^^^^^^
)
^
File "/Users/mimamu/myPython/garminweb_mimamu/venv/lib/python3.14/site-packages/garth/sso.py", line 135, in login
return _complete_login(client)
File "/Users/mimamu/myPython/garminweb_mimamu/venv/lib/python3.14/site-packages/garth/sso.py", line 260, in _complete_login
oauth1 = get_oauth1_token(ticket, client)
File "/Users/mimamu/myPython/garminweb_mimamu/venv/lib/python3.14/site-packages/garth/sso.py", line 151, in get_oauth1_token
resp.raise_for_status()
~~~~~~~~~~~~~~~~~~~~~^^
File "/Users/mimamu/myPython/garminweb_mimamu/venv/lib/python3.14/site-packages/requests/models.py", line 1026, in raise_for_status
raise HTTPError(http_error_msg, response=self)
requests.exceptions.HTTPError: 401 Client Error: Unauthorized for url: https://connectapi.garmin.com/oauth-service/oauth/preauthorized?ticket=ST-0273168-icMNbOhcDmJToAzDdOvm-cas&login-url=https://sso.garmin.com/sso/embed&accepts-mfa-tokens=true
127.0.0.1 - - [17/Mar/2026 06:55:04] "POST /login HTTP/1.1" 401 -

[bart-antczak]

I have that problem too. It looks like it.

[TheMegamightyRedRooster]

Same here for the last 10 hours

[tobias-goertz]

Same issue here, 401 on oauth/preauthorized since this morning. Garth 0.5.21, garminconnect 0.2.40.

[cyberjunky]

I just tested (on new pc) and it works fine, still an issue for your guys?
Did you try to remove old tokens?

[cyberjunky]

Using garminconnect 0.2.40 and garth 0.6.3 btw

[llalundo]

thanks for checking. i still get Unauthorized for url: https://connectapi.garmin.com/oauth-service/oauth/preauthorized?ticket=ST-0332794-OnDgGZnafvFPwIseCeKD-cas&login-url=https://sso.garmin.com/sso/embed&accepts-mfa-tokens=true

and (sorry): i don't know what it means to 'remove old tokens'.

[cyberjunky]

thanks for checking. i still get Unauthorized for url: https://connectapi.garmin.com/oauth-service/oauth/preauthorized?ticket=ST-0332794-OnDgGZnafvFPwIseCeKD-cas&login-url=https://sso.garmin.com/sso/embed&accepts-mfa-tokens=true

and (sorry): i don't know what it means to 'remove old tokens'.

What do you us on top of this library? Often that script/software stores the oauth tokens in your home directory .garminconnect to re-use on next login. (demo.py does this) Maybe deleting and recreating them works. I have no access to my other system to try with old tokens.
Also you use MFA right?

[llalundo]

i don't use mfa on connect.garmin.com currently. so i used user and password. and until yesterday my app was able to login with my (not very professionally) worked out code.

i'll check for .garminconnect in my home directory... (mac os). found nothing. my code (i think) stores nothing for reuse. i simply logged in again when necessary.

[llalundo]

Update (to figure out what's happening): i tried with the demo.py here in the repo.

• not successful with my garmin account that i use, demo.py gives 'authentication failed'.
• i created a second garmin account. demo.py can log in, everything works.

trying to figure out what's different.

[cyberjunky]

Update (to figure out what's happening): i tried with the demo.py here in the repo.

• not successful with my garmin account that i use, demo.py gives 'authentication failed'.
• i created a second garmin account. demo.py can log in, everything works.

trying to figure out what's different.

I also tried with new login with account without MFA enabled, also works, although demo.py give a error on user name None, fixing that.
Did you already logged in before using demo.py with your old garmin account, on same computer (so didn't ask for emai/password this time) ?

[tobias-goertz]

I Can confirm: this seems to be account-related, not a library issue.

Old account → 401 on preauthorized. New account (created Oct 2025, MFA enforced by default) → works fine with the same code. @llalundo Your new account has likely MFA enforced as well I assume?

Looks like Garmin changed something for legacy accounts, or they started blocking certain accounts.

[cyberjunky]

Maybe login in to connect.garmin.com, perhaps they show something (new agreement, mfa requirement etc) ?

[tobias-goertz]

Nope, nothing. I turned on MFA, but that did not help, still the same 401 on /preauthorized. I think we need to wait a day or two, in case its a sort of migration going on.

[llalundo]

@tobias-goertz - i created the new account on connect.garmin.com and no MFA was enforced. i even don't see where i would change that. but i found that it's possible on www.garmin.com.

[bart-antczak]

This is definitely an account-related issue, because I tested it on my partner’s account and was able to download the data without any problems. It just doesn’t work on my account. It returns the same error message. There are no new terms. The only option is to wait more than 24 hours and see if it starts working.