My app-specific password, using on Thunderbird, seems to keep expiring after some time (don't use it that often so I don't know how long it takes to expire).

I will try to send an e-mail and Thunderbird will say the password is incorrect, so I will log into the Zoho Account Settings page, generate a new one, and it will then work. But a few weeks later I will try sending another e-mail and yet again it says the password is incorrect.

Is there any built-in app-specific password expiration period?