[Exchange 2007-2013 co-existance scenario - Outlook cannot connect to the new server.]

The problem: After installing the Exchange 2013 server in a co-existence scenario with existing server exchange 2007 the outlook cannot connect to the new mailboxes, created in Exchange 2013, showing the credentials window and following error: “There is a problem with the proxy servers's security certificate. The name on the security certificate is invalid or does not match the name of the target site [server.domain.com]. Outlook is unable to connect to the proxy server. (Error Code 0).”

The owa access for the same mailboxes works fine and sending/receiving emails is possible.

When trying to open https://*-mail-01.*.local/rpc in the browser, it asks for credentials and then gives error 404.

Configuration data:

1. Local domain aka *.local
   
2. Mail domain of @**.net
   
3. Exchange server 2007 sp3 *-mail.*.local
   
4. Exchange server 2013 cu9 *-mail-01.*.local
   
5. Certificate mail.*.local contains following namespaces:
   

• mail.*.local
  
• AutoDiscover.*.local
  
• Autodiscover.**.net
  
• *-MAIL-01
  
• *.local
  
• **.net
  
• *-mail-01.*.local
  
• Legacy.*.local
  
• Mail.**.net
  

Certificate is imported to both old and new exchange servers.

SMTP, IMAP, POP and IIS are signed by the new certificate in the Exchange 2013 server.

* - company internal domain name

** - company external email domain

1. DNS records:
   
   • Autodiscover: ip of Exchange 2013
     
   • Legacy: ip of Exchange 2007
     
   • MAIL.*.local: ip of Exchange 2013
     
   
   

1. Accepted Domains: **.net (standard domain), *.local
   
2. Virtual namespaces (as configured on the Exchange 2013 server:
   

Directory

URL (internal and external)

Authentication

Autodiscover

Integrated windows, standard

Ecp

https://mail.*.local/ecp

Standard, formular-based

EWS

https://mail.*.local/ews/exchange.asmx

Integrated windows

Microsoft-Server-ActiveSync

https://mail.*.local/Microsoft-Server-ActiveSync

SSL-Activated, Standard,Client Certificate Ignore

OAB

https://mail.*.local/OAB

owa

https://mail.*.local/owa

Form-based Domane\Username