I can't sign in to GPSLarp
A sign-in screen covers the window. You press the button, a browser opens, and either nothing comes back or the app is still asking when you return to it.
Signing in happens in your browser and finishes by handing the result back to the app over a connection to your own machine. Almost every failure here is one end of that hand-off, not your password.
01Why there is a sign-in at all
Downloading GPSLarp needs no account — the installer asks for nothing, no email address and no card. Running it does. The account is what the free run of each mode is counted against, what a subscription attaches to, and what later lets you export or delete everything held about you.
One consequence is worth knowing before you go looking for a bug elsewhere: the sign-in screen covers the whole window. A build that cannot get past it looks like whatever you were trying to reach is broken. This has been reported as "the map is missing", and the map was fine.
02What the button actually does
Three things, in order:
- The app opens a small listener on your own computer — the address
127.0.0.1, which is your machine talking to itself, on a port the operating system picks. Nothing outside your Mac can reach it. - It opens your default browser at the identity provider's sign-in page, carrying a one-time value that ties that browser visit to this app window.
- When you finish in the browser, the provider sends the browser back to that local address, and the app picks the result up from there.
Your password is typed into the provider's page in your browser, and never into GPSLarp. The app never sees it.
03The browser opened and nothing came back
01Finish it in the browser window that opened
Not a different one. The hand-off is tied to the visit the app started — copying the address into another browser, or starting again in a second tab, produces a sign-in that completes for you and never reaches the app.
02Look for a browser window that never came to the front
If your browser was not already open, macOS sometimes puts the new window behind everything. The page is sitting there waiting; it just is not where you looked.
03Come back to GPSLarp and let it notice
You do not have to press anything in the app. It is watching for the hand-off and stops watching after a few minutes — so if you left the browser open for a while and came back, start again rather than waiting longer.
04Try once more, from the app
Each attempt gets a fresh local port and a fresh one-time value, so a second try is genuinely a clean start rather than a retry of the same thing. This is worth doing before anything below it.
05Check nothing is blocking your own machine
Security software that filters loopback connections, or a proxy
configured to catch everything, can stop the browser reaching the listener
on 127.0.0.1. The symptom is exactly this one: the browser says
it worked and the app never hears about it. Pause that software for a
moment and try again.
The app will not tell you which of these it was
When a sign-in fails, the reason is recorded and nothing puts it on the screen — you get the sign-in screen back with no explanation. That is a gap in the app rather than a subtlety of your setup, and it is the reason this page has to list five possibilities instead of pointing at one.
04"You're offline"
A session that has been established keeps working without a network for a while — fourteen days from the last time it was checked with the provider. Past that, GPSLarp stops accepting it and says so.
The fix is a network connection. Connect, and sign in again; there is nothing to repair.
Worth knowing about the boundary: a session the provider actively rejects ends immediately, and a session that simply could not be checked does not. Those are deliberately different, so a bad connection cannot sign you out.
05If that did not work
The browser shows an error from the identity provider. That is the provider refusing before GPSLarp is involved at all. Try a different sign-in method on that page — a different provider, or an email address.
You have an old copy of GPSLarp. Very early builds could not sign in at all, through no fault of anybody's setup, and the symptom was exactly this screen. Getting the current build is the fix and it is worth ruling out early: download the current version and install it over the old one.
Nothing above applies. The honest limit: this is the newest part of the product and the least exercised. If you have worked through everything here, you have done the part that is yours to do.