Today I met a strange issue in Exchange 2013 new installation.

Incoming emails were not arrived at the mailboxes. The NDR shows “Remote host said: 451 4.7.0 Temporary server error. Please try again later. PRX2”

I checked everything on the DNS side and no joy !!!

The server used were a multi-role server and found as this is a bug in the program.

The fixย is:

1. Create host file entries on the server with two names: server,server.domain.localย 

2. Restart “Microsoft Frontend Transport” and “Microsoft Exchange Transport” services

After doing the procedure, inbound emails has been arrived suddenly !!!

Hope this will help you if you met issues in Exchange 2013 Multi-role server infrastructure


  1. Hi Manu,

    I have this same issue with an Exchange 2013 SP1 server ๐Ÿ™


    • Paul

      My server has been up for awhile and just started having this issue, started dropping some emails while delivering others. my server is now going strong for 2 hours without deferring any. Thanks!!


  2. Jaap,
    Hope this reading has helped you ๐Ÿ™‚


  3. Sinan

    I have the same Problem please help meh.
    I write in de Windows\system32\Drivers\etc. the host file entries with ip address
    but it doesnt work.

  4. Seth

    I have just installed Exchange 2013 cu5 and got this same error on a server with two nics.

    Adding entries to the Exchange server’s host file as described above cured the problem for me.
    E.G. (tab)
    and (tab)

    FYI for noobs: hosts file is usually located in C:\Windows\System32\drivers\etc
    Open notepad with Admin rights (to allow saving of new entries) and browse to above location.


  5. Hi,
    Check the backend/frontend receivers .. backend = 2525, frontend 25…
    I you use them the wrong way you will take down you server ๐Ÿ™‚

  6. Harish

    Thanks Buddy.
    I had same issue and by adding host file entry it resolved.

    Thanks a ton.

  7. Rajan

    Thanks dude, this solved my issue ๐Ÿ™‚

  8. CarlosA

    Like always Manu your posts are extremely helpful.

    Thank you

  9. kaderb

    Thanks…. incredible… it’s been 20 years i’ve write nothing in hostfile…


  10. Thank you very much this also worked for me, when you make the change, if nothing happen straight away you may have to bounce/reboot server, after that the emails will just flow in like water

  11. Blenda

    Thanks, it saved me ๐Ÿ™‚

  12. Shruthi

    Thank you it worked for me as well


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