I once had an app send me a code in the email. But if I opened my email app to check the code, and then return to the app to enter it, it would lose context! It

I once had an app send me a code in the email. But if I opened my email app to check the code, and then return to the app to enter it, it would lose context! It would ask me to enter my email again, and proceeded to send a new code. There was no way to log in using only my phone.