I'm troubleshooting an Outlook Anywhere issue with a new Exchange 2010 server. The server in question, MS2010, is behind a SonicWALL NSA 2400 device and works wonderfully except for Outlook Anywhere. Outlook Anywhere works internally and I've verified (through Ctrl-Right Click --> Connection Status) that I'm able to connect to MS2010 over HTTPS.

When trying to connect to the server using HTTPS from outside the firewall, I'm unable to do so. A Wireshark trace shows 30 or so successful HTTPS packet transmissions, and then it fails with 3 straight transmissions to a destination port of 135. I have no idea why my computer is attempting to access anything on port 135 since I've setup my profile to use HTTPS on both slow and fast connections.

I'm 99% certain that the firewall is configured correctly. I run Outlook Web Access (also HTTPS) on the same server and there are no issues with access.

EDIT: My Autodiscover settings are correct (as far as I can tell). My server passes the Outlook Anywhere and Autodiscover tests at https://www.testexchangeconnectivity.com/.

I've been using the RPCPing utility to troubleshoot and have come across the following results:

Internally-

>rpcping -t ncacn_http -s mail.mydomain.com -o RpcProxy=mail.mydomain.com -P "pk,mydomain,*" -I "pk,mydomain,*" -H 1 -u 10 -a connect -F 3 -v 3 -E -R none
RPCPing v2.12. Copyright (C) Microsoft Corporation, 2002
OS Version is: 6.1, Service Pack 1

RPCPinging proxy server mail.mydomain.com with Echo Request Packet
Sending ping to server
Response from server received: 200
Pinging successfully completed in 93 ms

Externally-

>rpcping -t ncacn_http -s mail.mydomain.com -o RpcProxy=mail.mydomain.com -P "pk,mydomain,*" -I "pk,mydomain,*" -H 1 -u 10 -a connect -F 3 -v 3 -E -R none
RPCPing v6.0. Copyright (C) Microsoft Corporation, 2002-2006
 Enter password for RPC/HTTP proxy:

 RPCPing set Activity ID:  {fc8411ba-2987-4175-b37b-801dc69d5ff9}
 RPCPinging proxy server mail.mydomain.com with Echo Request Packet
 Setting autologon policy to high
 WinHttpSetCredentials for target server called
 Error 87 : The parameter is incorrect.
 returned in WinHttpSetCredentials
 Ping failed

What should I be checking in order to troubleshoot my Outlook Anywhere issues? I'm using Windows 7 SP1 for internal and external access.

EDIT: Autodiscover.xml content

<?xml version="1.0"?>
<Autodiscover xmlns:xsd="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://schemas.microsoft.com/exchange/autodiscover/responseschema/2006">
<Response xmlns="http://schemas.microsoft.com/exchange/autodiscover/outlook/responseschema/2006a">
<User>
<DisplayName>John Doe</DisplayName>
<LegacyDN>/o=MYDOMAIN/ou=Exchange Administrative Group (FYDIBOHF23SPDLT)/cn=Recipients/cn=pk</LegacyDN>
<DeploymentId>d35170cc-f3a7-42c5-9427-1f554a469126</DeploymentId>
</User>
<Account>
<AccountType>email</AccountType>
<Action>settings</Action>
<Protocol>
<Type>EXCH</Type>
<Server>MS2010.MYDOMAIN.local</Server>
<ServerDN>/o=MYDOMAIN/ou=Exchange Administrative Group (FYDIBOHF23SPDLT)/cn=Configuration/cn=Servers/cn=MS2010</ServerDN>
<ServerVersion>738180DA</ServerVersion>
<MdbDN>/o=MYDOMAIN/ou=Exchange Administrative Group (FYDIBOHF23SPDLT)/cn=Configuration/cn=Servers/cn=MS2010/cn=Microsoft Private MDB</MdbDN>
<ASUrl>https://MS2010.MYDOMAIN.local/EWS/Exchange.asmx</ASUrl>
<OOFUrl>https://MS2010.MYDOMAIN.local/EWS/Exchange.asmx</OOFUrl>
<OABUrl>http://MS2010.MYDOMAIN.local/OAB/2c34c9f5-5521-4c8c-b684-538df815052a/</OABUrl>
<UMUrl>https://MS2010.MYDOMAIN.local/EWS/UM2007Legacy.asmx</UMUrl>
<Port>0</Port>
<DirectoryPort>0</DirectoryPort>
<ReferralPort>0</ReferralPort>
<PublicFolderServer>MS2007.MYDOMAIN.local</PublicFolderServer>
<AD>dc1.MYDOMAIN.local</AD>
<EwsUrl>https://MS2010.MYDOMAIN.local/EWS/Exchange.asmx</EwsUrl>
<EcpUrl>https://MS2010.MYDOMAIN.local/ecp/</EcpUrl>
<EcpUrl-um>?p=customize/voicemail.aspx&amp;exsvurl=1</EcpUrl-um>
<EcpUrl-aggr>?p=personalsettings/EmailSubscriptions.slab&amp;exsvurl=1</EcpUrl-aggr>
<EcpUrl-mt>PersonalSettings/DeliveryReport.aspx?exsvurl=1&amp;IsOWA=&lt;IsOWA&gt;&amp;MsgID=&lt;MsgID&gt;&amp;Mbx=&lt;Mbx&gt;</EcpUrl-mt>
<EcpUrl-ret>?p=organize/retentionpolicytags.slab&amp;exsvurl=1</EcpUrl-ret>
<EcpUrl-sms>?p=sms/textmessaging.slab&amp;exsvurl=1</EcpUrl-sms>
</Protocol>
<Protocol>
<Type>EXPR</Type>
<Server>mail.mycompany.com</Server>
<ASUrl>https://mail.mycompany.com/ews/exchange.asmx</ASUrl>
<OOFUrl>https://mail.mycompany.com/ews/exchange.asmx</OOFUrl>
<OABUrl>https://mail.mycompany.com/OAB/2c34c9f5-5521-4c8c-b684-538df815052a/</OABUrl>
<UMUrl>https://mail.mycompany.com/ews/UM2007Legacy.asmx</UMUrl>
<Port>0</Port>
<DirectoryPort>0</DirectoryPort>
<ReferralPort>0</ReferralPort>
<SSL>On</SSL>
<AuthPackage>Basic</AuthPackage>
<CertPrincipalName>msstd:mail.mycompany.com</CertPrincipalName>
<EwsUrl>https://mail.mycompany.com/ews/exchange.asmx</EwsUrl>
<EcpUrl>https://mail.mycompany.com/owa/</EcpUrl>
<EcpUrl-um>?p=customize/voicemail.aspx&amp;exsvurl=1</EcpUrl-um>
<EcpUrl-aggr>?p=personalsettings/EmailSubscriptions.slab&amp;exsvurl=1</EcpUrl-aggr>
<EcpUrl-mt>PersonalSettings/DeliveryReport.aspx?exsvurl=1&amp;IsOWA=&lt;IsOWA&gt;&amp;MsgID=&lt;MsgID&gt;&amp;Mbx=&lt;Mbx&gt;</EcpUrl-mt>
<EcpUrl-ret>?p=organize/retentionpolicytags.slab&amp;exsvurl=1</EcpUrl-ret>
<EcpUrl-sms>?p=sms/textmessaging.slab&amp;exsvurl=1</EcpUrl-sms>
</Protocol>
<Protocol>
<Type>WEB</Type>
<Port>0</Port>
<DirectoryPort>0</DirectoryPort>
<ReferralPort>0</ReferralPort>
<Internal>
<OWAUrl AuthenticationMethod="Basic, Fba">https://MS2010.MYDOMAIN.local/owa/</OWAUrl>
<Protocol>
<Type>EXCH</Type>
<ASUrl>https://MS2010.MYDOMAIN.local/EWS/Exchange.asmx</ASUrl>
</Protocol>
</Internal>
<External>
<OWAUrl AuthenticationMethod="Fba">https://mail.mycompany.com/owa/</OWAUrl>
<Protocol>
<Type>EXPR</Type>
<ASUrl>https://mail.mycompany.com/ews/exchange.asmx</ASUrl>
</Protocol>
</External>
</Protocol>
</Account>
</Response>
</Autodiscover>