Application specific password lasts for 24 hrs

Application specific password lasts for 24 hrs

I've just set up two-factor authentication for my Zoho-mail. I have an iPad and an iPhone and do NOT want to use the Zoho-client on either. The built in clients rely on POP and SMTP.
So I set up application specific passwords for both devices. It works OK for 24 hrs, but after that period I can no longer log in to Zoho-mail from these devices and am forced to generate two new app-specific pws. Annoying – you bet. The documentation says these pws never expires, so what gives.

Best, 

Joern Wennerstroem