A customer with Microsoft Exchange 2010 suddenly reported email down situation, we found the databases to be Mounted and Outlooks were connected fine, it was just that when they were sending outbound email they were getting error Relay access denied Error 554 5.7.1

Your message wasn’t delivered due to a permission or security issue. It may have been rejected by a moderator, the address may only accept e-mail from certain senders, or another restriction may be preventing delivery.

The following organization rejected your message: mx1-us1.ppe-hosted.com.

Diagnostic information for administrators:

Generating server: -Exchange.Domain.com


mx1-us1.ppe-hosted.com #554 5.7.1 <shishir@pledgetechnologies.com>: Relay access denied ##

We troubleshoot the error and found that the issue to be with Smart host server with an US based company PPE.  PPE was acting as smart host as well as Spam protection for the Exchange server.  To troubleshoot and to eliminate the role of PPE

  1. We created a new Exchange Outbound connector, Under Organisation Configuration -> Hub Transport -> Send Connector
  2. This was configured as an Internet connector ( to relay emails directly to internet) and not via the smart host.
  3. We disable the existing smart host send connector and started outbound email delivery directly via internet, this fixed our outbound emails
  4. After ensuring the issue was with PPE  smart host solution, We didn’t try fixing inbound connection as such (our MX was pointed to PPE ) instead we called them and had our PPE issue resolved.

Incase you also want to fix the incoming and want to remove the role of SmartHost/ Spam filter then follow the steps above to create an outbound send connector to directly relay to internet and follow the below steps to configure inbound email delivery to Exchange Server directly.

  1. Find out the public IP of your organisation router/firewall behind which you have the Exchange server
  2. Configure a Port forwarding rule from the public IP to the internal IP of your Exchange server for Port TCP 25 and TCP 587
  3. Change the MX record ( configured at the public DNS console of your name server/domain registerar such as Godaddy or Network Solutions) to point to the Public IP of your organisation.

Hopefully this should help you with the issue or else feel free to reach us for immediate paid support or start a thread on the forum for expert community support.

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An automobile enthusiast at heart and computer geek by profession, started my Career with MS in 2005.Left Jobs and started Pledge Technologies (the parent company to Grishbi) back in 2009.We have been providing IT consulting to various Small and Medium businesses across US and UK since then.Our company specialises in Microsoft Server technologies like AD, Exchange, the rest and with numerous Office 365 migrations under our belt, we quite an expert with that too. Whatever we learn in our day to day life, we share it back on Grishbi as a Thank for all the love and support our customers have given us.
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