Unmatched deep-link in Ionic 3

I'm apps flow goes like this:

1. Launch App
2. Spotify 'Allow App Access' page is opened in the browser (Chrome),
3. The user give the app permission and is redirect to https://appurl.com/spotify-callback/,
4. That URL is deep-linked so that my app is now opened again,
5. The deep-link plugin should now match /spotify-callback/ and open the page named SpotifyCallbackPage should be opened but I get the error console.error: Got a deeplink that didn't match

My deep-link code looks like:

deeplinks.route({
                '/spotify-callback/': SpotifyCallbackPage
            }).subscribe((match) => {
                // match.$route - the route we matched, which is the matched entry from the arguments to route()
                // match.$args - the args passed in the link
                // match.$link - the full link data
                console.log('Successfully matched route', match);
            }, (nomatch) => {
                // nomatch.$link - the full link data
                console.error('Got a deeplink that didn\'t match');
                console.log(nomatch);
            });

The URL sent to the router is:

https://appurl.com/spotify-callback/#access_token=random-access-token-here&token_type=Bearer&expires_in=3600

The full error message is:

error opening ws message: {"category":"console","type":"log","data":["On deep 
            link",{"url":"https://appurl.com/spotify-callback/#access_token=random-access-token-here&token_type=Bearer&expires_in=3600","path":"/spotify-callback/","scheme":"https","host":"appurl.com","fragment":"access_token=random-access-token-here&token_type=Bearer&expires_in=3600","extra":{"org.chromium.chrome.browser.eenp":["io.ionic.starter"],"org.chromium.chrome.browser.referrer_id":21,"com.android.browser.application_id":"com.android.chrome"}}]}
[16:28:02]  console.error: Got a deeplink that didn't match 

I've tried different URLs and endpoints in the router but none of them will match. Does anybody know what I should be trying to match?