Unauthorized error with Fluent SMTP

I have the exact same same issue, I tried to disconnect and connect again, and here is the output I see from the auth page from Microsoft:

(https://login.microsoftonline.com/common/oauth2/v2.0/authorize?state=…)

Sorry, but we’re having trouble signing you in.

AADSTS700016: Application with identifier ‘qnD8Q~7u7mRukoPzt1L08N9jp~Cch6w1j_RrVcaw’ was not found in the directory ‘mywebpage.com’. This can happen if the application has not been installed by the administrator of the tenant or consented to by any user in the tenant. You may have sent your authentication request to the wrong tenant.

• This reply was modified 5 months, 4 weeks ago by heyflavio.

I am using FluentSMTP on a view website and it works very well there.

But on a website with the external email provider Microsoft 365 it doesn’t work at all. However, I have gone through the registration process and have received the API token and secret. I was also able to enter the API token and secret in the FluentSMTP registration form.

I did not forget to allow the website server to handle the routing of external emails, and in my opinion I also configured the external nameservers correctly.

However, sending an email doesn’t work. I sent a test email and it failed with the unauthorised error.

What can I do?

Same problem here. Trying to set up FluentSMTP. Double and triple-checked the credentials, and got my webhost involved to look at things from their end. Frustrating. If anyone has a solution to this, I’d sure appreciate it

Hello @impactbt,

I understand you’re experiencing an “unauthorized error” when trying to send test emails. Let’s troubleshoot this together.

Here’s a possible solution that I’d recommend you check:

Incorrect App Callback URL: Ensure that the App Callback URL you’ve provided in the FluentSMTP settings is correct and includes all necessary parameters. Verify that it matches the URL in your Azure App registration.

If that doesn’t resolve the issue, here are some other suggestions:

• Insufficient permissions:?Confirm that the email address you’re using as the sender has the necessary permissions to send emails and has a valid Office365 subscription.
• Incorrect Account Type:?The Azure App must be created with the account type “Accounts in any organizational directory (Any Azure AD directory – Multitenant) and personal Microsoft accounts (e.g. Skype, Xbox).”
• Incorrect Logged-in Account:?When authorizing the connection, ensure that you’re using the same email account that was used to create the Azure App.
• Domain Verification:?Verify that the domain you’re sending emails from is verified in Microsoft Office365.

If the issue persists, please refer to the Office 365 API documentation provided in the support article.

Feel free to keep me updated on your progress, and let me know if you need any additional support.

Hello @heyflavio,

I would recommend double-checking that the account you used to create the Azure app is the same one you used to generate the token for Fluent SMTP. Could you please check and confirm?

Hello @pagan3,

Please double-check that you have entered the Client Secret Value, and not the Client Secret ID, when setting up Fluent SMTP. This error can occur when the wrong information is entered.