To clear the cache of your Expatrio App; 

Please hold the 'Help' button at the bottom right of the log-in page for five seconds.

This will unpair your current device.

Clearing the cache is especially helpful if you are having trouble receiving the SMS verification code on your phone or would like to try the device pairing again for any other reason.

Having trouble receiving the verification code may be due to many reasons; for more details, please check this article.