Kindly help in the following error which started few hours ago

Hi @Keith D, 

Thank you for reaching out Microsoft Q&A Forum and sharing your experience. 

It looks like your tenant has reached the limit for outgoing emails due to the anti-spam system temporarily blocking further sends. This typically occurs when a large volume of emails is sent from one or more addresses within the tenant. 

If you're not the administrator of your email account, you'll need to reach out to someone who has admin access to your organization's Office 365 environment. They can review the mail flow connectors in the Exchange Admin Center and remove any unfamiliar or unauthorized connectors that may be used to send emails from your tenant. 

Once that's done, the next step is to open a support ticket. Please ask your administrator to sign in to the Microsoft 365 Admin Center and submit a support request directly from there. A support engineer will then get in touch to assist further. 

For more details on related error codes and resolution steps, you can refer to this Microsoft support article:  NDR error codes 550 5.7.703, 550 5.7.705, 550 5.7.708, and 550 5.7.750 - Microsoft Support 

After the underlying cause of the issue has been addressed, your organization’s IT admin should contact Microsoft Support to request removal of the block. 

Contact Microsoft Support  

• Ticket Support: In the Microsoft 365 Admin Center>Support>Help & Support. You can raise support ticket  
• Phone Support: Microsoft provides customer service phone numbers based on your region. You can find the appropriate contact number here.  

I hope this information is helpful. Please follow these steps and let me know if it works for you. If not, we can work together to resolve this.  

Thank you for your patience and your understanding. If you have any questions, please feel free to reach out.  

Best regards,  

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