Did you try logging in with Hivesigner? The first time you login to a new app in Hivesigner, you need the active key, for subsequent logins the posting key.
If you don't want to enter Hive passwords on your phone, you can also go to https://travelfeed.io/ and create a new account (e.g. by email, facebook google) and connect your Hive account to it under https://travelfeed.io/dashboard/integrations/hive. You can then log in with email/facebook/google on your phone and posting to Hive will still work :)