SMTP error "Must issue a STARTTLS command first" when creating an alert in SharePoint 2010

Question

We have an on premises SharePoint 2010 SP1 environment with our exchange environment in Office 365.  Alerts in SharePoint worked with our SMTP server until we migrated exchange to the cloud.  At that point we had to reconfigure our SMTP server to act as a relay to forward alert emails to Microsofts SMTP server

I have configured SMTP using the following instructions found in this post  http://support.microsoft.com/kb/2600912

I have created a valid TFS certificate and the communication between our on premises SMTP server and Microsoft's SMTP server is functioning.  I can telnet into the server using port 587 and port 25.

When I create a new alert in SharePoint 2010 I receive the following error message in the ULS logs

#160005: Bad response from SMTP host'server.domain.com': 530 5.7.0 Must issue a STARTTLS command first .

I have replaced our server name above with a fictitious name.

I cannot find a resolution for this problem and it is beginning to become a business issue as it is preventing any alerts from our SharePoint environment from being sent.  I have researched this error thoroughly and talked to many people but have not been able to find any answers that would even lead me to a resolution.  Right now I am at a loss and am hoping that someone may have seen this issue before and could provide an explaination of the cause at the least.

Thank you in advance for any help you can provide.

Answer 1

Hi,

Since your issue is about Office 365, I suggest you post your issue into the following forum for a better solution.

http://community.office365.com/en-us/forums/166.aspx

There are two major things to note here. Firstly, the Outbound SMTP server is NOT one of the Online Services servers. The reason for this is that to deliver mail to any of the Online Services servers, you need to authenticate, use SSL, and use a nonstandard SMTP port. (You can find complete instructions on relaying messages to BPOS and Exchange Online here). What we therefore need to do is to set up our very own SMTP server that can relay these messages for us.

For the detailed information about integrating SharePoint on premises with Office 365(BPOS former name), check out the following articles:

http://whitepages.unlimitedviz.com/2010/09/integrating-sharepoint-on-premises-with-bpos-and-exchange-online-part-1outbound/

http://blogs.kma-llc.net/kma/2011/09/quick-tip-smtp-relay-to-bpos-outgoing-emails-by-max-herve.html

Thanks,

Rock Wang

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Rock Wang TechNet Community Support

Answer 2

Thank you for your response and for the information.  Unfortunately I have gone through all of these articles previously.  The issue is not with getting our on premise SMTP server and the online SMTP server to talk.  Right now those communicate without errors.  The issue I am having is getting our SharePoint server to communicate with our on premises SMTP server using TLS on port 587. 

I have spoken to the Office 365 technical team and they state that it is an issue between our on premise SharePoint and SMTP environments and they do not support it.  I agree with them even though this issue is due to their required settings it is still about communications issues within our environment.

I am hoping someone has seen this error before and has found a fix or even a work around for it as it is becoming a business critical issue.  I will take your advice and post this on the Office 365 forum in hopes that someone there will have an answer.

Thank you again.

Answer 3

Hi,

TLS is only required on TCP port 587 when your on-premise SMTP server communicates with Office 365 Exchange online server. SharePoint server should use port 25 to talk to on-premise SMTP server.

The whole mail flow should be as follows:

SharePoint server ---25(anonymous)> on-premise SMTP server ---587(TLS)> Office 365 Exchange online server

Firstly, please make sure you input your on-premise SMTP server in the central admin on SharePoint server,

Secondly, On the Access tab, click Authentication, click to select the Anonymous access check box, and then click OK.

Thirdly, On the Relay tab, select Only the list below, type the IP addresses of the client computers(SharePoint server’s IP address)that will be sending the email messages, and then click OK.

Thanks,

Rock Wang

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Rock Wang TechNet Community Support