"InvalidSenderError: Unauthorized sender error" suddenly started happening on our project.

[Andrea Cimino]

We have an appengine project that is online by several years. A couple of weeks ago we started receiving the error in the subject, and I tried to investigate the problem.

By looking at the documentation:

"All email addresses on the Email API Authorized Senders list need to be valid Gmail or Google-hosted domain accounts."

The question is: what is a google-hosted domain account?

 A domain hosted by https://domains.google/#?

A domain registered and configured at https://console.cloud.google.com/appengine/settings/domains?

Ww have already a domain set:

	Nome dominio personalizzato	Sicurezza SSL	ID certificato	Tipo di record	Dati	Alias
	www.ourdomain.com	Gestito da Google, a rinnovo automatico	-	CNAME	ghs.googlehosted.com	www

Maybe we should set all the domain and not only www.ourdomain.com?

I am purposely omitting personal information.

Thanks for your support

[George (Cloud Platform Support)]

Hello Andrea, 

You can find details relevant to your question "what is a google-hosted domain account" on the "Mail API Overview" documentation page, namely in the "Who can send mail" sub-chapter. 

"App Administrators can add the following accounts to the list of Authorized Senders:

Their own email address

Any group for which they are an Owner or Manager

Applications hosted in a G Suite domain: noreply@[DOMAIN].com, as long as noreply@[DOMAIN].com is a valid account (user or group)". 

[Andrea Cimino]

Il giorno domenica 21 aprile 2019 19:30:27 UTC+3, George (Cloud Platform Support) ha scritto:

Hi George,

unfortunately, at least from my point of view, the documentation is not really clear.

"All email addresses on the Email API Authorized Senders list need to be valid Gmail or Google-hosted domain accounts. App Administrators can add the following accounts to the list of Authorized Senders".

Still is not clear what is a Google hosted domain account. 

I know just that our service was working perfectly fine until 15 days ago and now we have this error.
If you could please give as good pointers to how to get a "Google hosted domain account" it would be very nice,
as we are stuck and we don't know how to fix this error. 

[Khaled Wagdy]

Hello, can you check the email sender lists? https://console.cloud.google.com/appengine/settings/emailsenders and make sure that the account(s) you are sending from are listed there?

Also, I'm curious, are the emails you are sending from a gmail.com or Google Apps for work (GSuite) email address(es)?

[Andrea Cimino]

The address is correctly listed (every was working fine until 15 days ago).

The address is neither a gmail.com or Google Apps for Work (GSuite).

Some times ago we registered for GSuite to have our email sender working, but 2 years ago this requirement was not needed anymore according to the documentation, so we disabled the GSuite account (2 years ago). I think something the email sender requirements have changed during time, so we falled in this problem.

Recently we have received a mail from google stating:

Greetings from Google,

It appears you have not used your Google Account managed for the "ourdomain.com " domain in the last 365 days.

If you do not take one of the corrective measures described below, Google will delete the account on 27 March 2019 or at a later date.

So this is what happened. So we really need a Gsuite account for sending emails?

I think at this stage is migrating to other services such as Sendgrid as advised.

[Andrea Cimino]

Sorry: I think at this stage the best solution is migrating to other services such as Sendgrid as advised for sending emails.

[Khaled Wagdy]

Oh I see, 27 March sounds like a little more than 15 days ago, but it could be that the systems picked it up later and therefore you started seeing the unauthorized sender error.

You probably need to switch as you said to another provider like Mailgun, Mailjet, or SendGrid.

Best of luck :)

[Khaled Wagdy]

Quick note, Mailgun pricing states the following, if you need to send a lot of bulk messages monthly:

As a Google Cloud Platform user, your first 30,000 messages are free every month. See the monthly pricing calculator on the sign up page for pricing on additional messages and volume discounts.

 

This is mentioned on this page: Sending Email with Mailgun "Pricing" section. You might want to compare the features too in case there are other aspects you need to consider in your app.

Good luck,

[Andrea Cimino]

Thanks for the support,

some times is very hard to troubleshoot the root cause of errors.

Kind regards.