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Outgoing server (SMTP) smtp.office365.com is unknown
archeon
Newbie
‎03-28-2015 01:35 AM

Hi,

since a few days I am not able to sent emails using my work email account from my home network.  I receive the error message "Outgoing server (SMTP) smtp.office365.com is unknown".  The SMTP server uses the port 587 and STARTTLS.

It is not an issue with my email client or my account settings nor outgoing mail in general since I am able to sent emails from my laptop at work or from other networks  and I am able to sent emails using my private email account from home.

I also understand that Verizon supports the port 587, thus I am a bit lost as to what the problem could be, especially since it worked before and I have not changed anything.

Any suggestions?

Thanks

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eljefe2
Master - Level 1
‎03-28-2015 07:08 AM

You might try changing the outgoing port to 465 and see if that corrects the problem.

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archeon
Newbie
In response to eljefe2
‎03-29-2015 11:41 AM

Thanks

Tried it, but did not work.

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tns2
Community Leader
Community Leader
‎03-29-2015 03:02 AM

Problem probably has nothing to with verizon.

Is smtp.office365.com a Microsoft mailing server?  If so ask them.  Either way find someone responsible for the server you are having trouble with.

ps verizon's servers will no longer support 587(something they have said for a couple years now and about to enforce), but they don't block you from using it to other servers.

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archeon
Newbie
In response to tns2
‎03-29-2015 11:41 AM

Thanks,

but unfortunately it is either verizon or my router. since with the same machine I have no trouble sending emails from that account if I am outside of my home.   However, I have not changed anything nor touched the router.

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gs0b
MVP MVP
MVP
In response to archeon
‎03-29-2015 11:57 AM

Open a command prompt and enter "ping smtp.office365.com".  You should see something like this:

   C:\Users\gs0b>ping smtp.office365.com

   Pinging outlook-nameast.office365.com [132.245.12.18] with 32 bytes of data:
   Reply from 132.245.12.18: bytes=32 time=59ms TTL=245
   Reply from 132.245.12.18: bytes=32 time=58ms TTL=245
   Reply from 132.245.12.18: bytes=32 time=58ms TTL=245
   Reply from 132.245.12.18: bytes=32 time=58ms TTL=245

   Ping statistics for 132.245.12.18:
       Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
   Approximate round trip times in milli-seconds:
       Minimum = 58ms, Maximum = 59ms, Average = 58ms

If you don't get the first line that shows the IP address of smtp.office365.com, you have a problem with DNS.  I use OpenDNS.

Good Luck.

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