Location:Home > Email Service Knowledge > Article content

19 Authentication Unsuccessful SMTP Office 365 Solutions

AotSendPro6Month Ago (10-08)Email Service Knowledge82
AotSend Email API Best 24+ Email Marketing Service (Price, Pros&Cons Comparison) What is a Managed Email API, How it Works? Best 25+ Email Marketing Platforms (Compare Authority,Keywords&Traffic)

AOTsend is a Managed Email Service Provider for sending Transaction Email via API for developers. 99% Delivery, 98% Inbox rate. $0.28 per 1000 emails. Start for free. Pay as you go. Check Top 10 Advantages of Managed Email API




1. Introduction

Encountering the "19 Authentication Unsuccessful" error when trying to send emails through SMTP using Office 365 can be frustrating. This error typically indicates that there's an authentication issue between your email client or application and the Office 365 SMTP server. In this blog post, we'll explore several solutions to help you resolve this problem.

2. Understanding the Error

The "19 Authentication Unsuccessful" error is a SMTP response code that suggests the client was not able to authenticate with the server. This can happen due to various reasons, including incorrect credentials, misconfigured email clients, or issues with the Office 365 account settings.



🔔🔔🔔

AOTsend Email API】:
AOTsend is a Transactional Email Service API Provider specializing in Managed Email Service. 99% Delivery, 98% Inbox Rate. $0.28 per 1000 Emails.
AOT means Always On Time for email delivery.


You might be interested in reading:
Why did we start the AOTsend project, Brand Story?
What is a Managed Email API, Any Special?
Best 25+ Email Marketing Platforms (Authority,Keywords&Traffic Comparison)
Best 24+ Email Marketing Service (Price, Pros&Cons Comparison)
Email APIs vs SMTP: How they Works, Any Difference?

🔔🔔🔔

3. Checking Your Credentials

The first and foremost step in troubleshooting this error is to verify your credentials. Ensure that you are using the correct username and password for your Office 365 account. Often, a simple typo or a misremembered password can cause authentication failures.

4. Reviewing Account Settings

After confirming your credentials, the next step is to review your Office 365 account settings. Log in to your Office 365 account and check if there are any security settings or policies that might be blocking SMTP authentication. Additionally, make sure that your account is not locked due to too many failed login attempts.

5. SMTP Settings and Configuration

19 Authentication Unsuccessful SMTP Office 365 Solutions

If your credentials and account settings are correct, the issue might lie in your SMTP configuration. When setting up your email client or application to use the Office 365 SMTP server, ensure that you are using the correct server address, port number, and encryption method. Office 365 typically requires TLS encryption on port 587 for SMTP authentication.

6. Firewall and Network Issues

Network-related issues can also cause authentication failures. Check if your firewall or network settings are blocking the SMTP port or if there are any other network restrictions that might be interfering with the connection.

7. Contacting Support

If you have followed all the steps above and the issue persists, it might be time to contact Office 365 support. They can help you further troubleshoot the problem and ensure that there are no account-specific issues causing the authentication failure.

Conclusion

The "19 Authentication Unsuccessful" error can be caused by various factors, ranging from incorrect credentials to misconfigured SMTP settings. By following the steps outlined in this blog post, you should be able to resolve the issue and successfully send emails through Office 365's SMTP server. Remember to always keep your credentials secure and regularly review your account and network settings to avoid any potential problems.

AotSend Email API Best 24+ Email Marketing Service (Price, Pros&Cons Comparison) What is a Managed Email API, How it Works? Best 25+ Email Marketing Platforms (Compare Authority,Keywords&Traffic)

AOTsend adopts the decoupled architecture on email service design. Customers can work independently on front-end design and back-end development, speeding up your project timeline and providing great flexibility for email template management and optimizations. Check Top 10 Advantages of Managed Email API. 99% Delivery, 98% Inbox rate. $0.28 per 1000 emails. Start for free. Pay as you go.


Scan the QR code to access on your mobile device.

Copyright notice: This article is published by AotSend. Reproduction requires attribution.

Article Link:https://www.aotsend.com/blog/p5913.html

“19 Authentication Unsuccessful SMTP Office 365 Solutions” 的Related Articles

18 Tips for Managing Outlook IMAP Password

18 Tips for Managing Outlook IMAP Password

#1 Understand IMAP and Its Role in Outlook When it comes to managing emails in Outlook, IMAP (Internet Message Access Protocol) plays a crucial role....

11 Tips to Retrieve Forgot My Gmail ID

11 Tips to Retrieve Forgot My Gmail ID

Have you forgotten your Gmail ID and are struggling to retrieve it? Don't worry, we've all been there. With the plethora of online accounts we manage...

15 Polite Email Reminder Templates to Boss

15 Polite Email Reminder Templates to Boss

In the fast-paced corporate world, effective communication with your superiors is crucial. Email remains a primary tool for such interactions, and mas...

Top 10 Email to WhatsApp Gateway APIs for Seamless Communication

Top 10 Email to WhatsApp Gateway APIs for Seamless Communication

Top 10 Email to WhatsApp Gateway APIs for Seamless CommunicationIn today's fast-paced digital world, seamless communication is key. One of the most ef...

12 Essential Android Push Mail Tips for Efficient Communication

12 Essential Android Push Mail Tips for Efficient Communication

In today's fast-paced world, efficient communication is key to personal and professional success. Android push mail services play a crucial role in ke...

7 Tips for Giving Notice by Email Professionally

7 Tips for Giving Notice by Email Professionally

In the modern workplace, email has become the primary means of communication, making it essential to master the art of professional email writing. Giv...