Title: Error: invalid_client
Last modified: August 22, 2016

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# Error: invalid_client

 *  Resolved [allbil](https://wordpress.org/support/users/allbil/)
 * (@allbil)
 * [11 years, 4 months ago](https://wordpress.org/support/topic/error-invalid_client-2/)
 * Hi
 * I have got the following error message when I tried to “Request permission from
   Google”
 * 401. That’s an error.
 * Error: invalid_client
 * no support email
 * [https://wordpress.org/plugins/postman-smtp/](https://wordpress.org/plugins/postman-smtp/)

Viewing 3 replies - 1 through 3 (of 3 total)

 *  Thread Starter [allbil](https://wordpress.org/support/users/allbil/)
 * (@allbil)
 * [11 years, 4 months ago](https://wordpress.org/support/topic/error-invalid_client-2/#post-5704778)
 * The problem is solved.
    Step 3 is not really correct: “In Sender Email Address
   enter your account’s email address. This should be the same address you login
   to Google with.”
 * This address should be the address you get with the key.
 * Now there is another problem, Postman shows following error message and it fails
   to send a test mail:
 * “Oh, bother! Your test message failed to send 🙁 … Communication Error [334].”
 *  Plugin Author [Jason Hendriks](https://wordpress.org/support/users/jasonhendriks/)
 * (@jasonhendriks)
 * [11 years, 4 months ago](https://wordpress.org/support/topic/error-invalid_client-2/#post-5704903)
 * Hi allbll, I saw 334 pretty often when I was developing this plugin, it’s a nasty
   one that implies the Client ID was in invalid in some way and for security, there
   is no additional message from Google to say why. I _do_ know that I can trigger
   the error by _not_ using my gmail address as the sender.
 * I also noticed sometimes that if I attempted to send email with the wrong address,
   that Gmail would silently invalidate the Client ID. So let’s start there. Go 
   back to the Google Developer Console, delete the old Client ID, create a new 
   Client ID and try it again.
 * Also, make sure that the gmail account you are using can login to Gmail on the
   web. I noticed after creating some new users for testing that if I attempted 
   to create and use a Client ID without ever having logged into Gmail, I would 
   not be able to authenticate.
 * Thanks for helping me test!
 *  Plugin Author [Jason Hendriks](https://wordpress.org/support/users/jasonhendriks/)
 * (@jasonhendriks)
 * [11 years, 4 months ago](https://wordpress.org/support/topic/error-invalid_client-2/#post-5704912)
 * Just to make sure there was nothing funny on Google’s end, I just created a new
   account, [jasontest383@gmail.com](https://wordpress.org/support/topic/error-invalid_client-2/jasontest383@gmail.com?output_format=md),
   and authentication and test went without a hitch. Let me know if re-creating 
   the Client ID and logging into gmail works for you.

Viewing 3 replies - 1 through 3 (of 3 total)

The topic ‘Error: invalid_client’ is closed to new replies.

 * ![](https://s.w.org/plugins/geopattern-icon/postman-smtp_7c7b78.svg)
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## Tags

 * [invalid_client](https://wordpress.org/support/topic-tag/invalid_client/)

 * 3 replies
 * 2 participants
 * Last reply from: [Jason Hendriks](https://wordpress.org/support/users/jasonhendriks/)
 * Last activity: [11 years, 4 months ago](https://wordpress.org/support/topic/error-invalid_client-2/#post-5704912)
 * Status: resolved