If you've double checked that your username and password is typed correctly, you may need to add Tango Card as a remote site. This allows the app in Salesforce to communicate with your Tango Card account. To add Tango Card as a remote site, just follow these steps:
- Log in to Salesforce at https://login.salesforce.com/
- Drop down your name in the upper right hand corner and click Setup.
- Click on Security Controls in lower left hand menu.
- Click Remote Site Settings.
- Click New Remote Site
- Create a name: TangoCard
- Enter the following URL as the Remote Site URL: https://api.tangocard.com/
- Click Save
Now you should be able to log into your Tango Card account inside the app in Salesforce.