Can I test mobile app with sandbox user?

[benlish]

Hi, Im using this url to direct pay:

https://www.paypal.com/qrcodes/managed/********-****-****-****-************?utm_source=bizapp

The problem is I cannot enter the Paypal app using my sandbox credentials, the app keep saying "check your info and try again".

Ive tried looking for Paypal app that support sandbox but no luck.

How can I test the payment using the app in Sandbox environment ?

thank you all.