GmailThread.reply works only first time

[jhaamit6666]

Hi all,

I am trying to send email programmatically in Google AppScript using GmailThread.reply(), but it works only first time. From 2nd time it gives me

Exception: Service invoked too many times for one day: email

So I have to run the script manually every time, but this doesn't make sense. Instead of this, I can send the emails manually. Does anybody know why is this happening?

I have used GmailMessage.reply() and GmailApp.sendEmail() also, but same error.

Thanks & regards,

[a_aleinikov]

Hi @jhaamit6666 ,

This error happens because Google Apps Script has daily email quotas — even for scripts.

Here’s what you should know:
– Free Gmail accounts have a daily script-sending limit (usually ~100/day).
– Google Workspace accounts have higher limits (up to ~1500/day), but still capped.
– Once you hit the quota, no script-based emails (GmailApp, GmailThread.reply, etc.) will work until the quota resets (next day).

Possible solutions:
 Check your current quota in Apps Script → Project Settings → Quotas.
If you need higher limits, consider using a Google Workspace account.
 For very large volumes, integrate with Gmail API + service account + proper authorization, which can handle more controlled, scalable sending.

[jhaamit6666]

I don't even send 100 emails/day, and it says, 

Exception: Service invoked too many times for one day: email

Also, on running the script again, it works only the first time, means it sends one email, and later throws the error.

I also checked Apps Script → Project Settings,

but I can see that Project settings has Google Apps Script API toggle which is off.