Proxy Manager How-To

Authentication error 535.5.7.3

I keep getting an authentication error (535. 5.7.3 Authentication unsuccessful) when I try to send a message. I am sure the password is correct.

If Basic Authentication is disabled for your mailbox, your administrator can configure Azure to let Proxy Manager use OAuth2 Authentication. This way the credentials are never stored locally and never sent across the wire. See Installing Proxy Manager as an Application in Microsoft Azure Active Directory for more details.

If you want to enable Basic Authentication, see Enable or disable authenticated client SMTP submission (SMTP AUTH) in Exchange Online and What are security defaults?.

Enter a Proxy Manager license key

I have received a Proxy Manager license key. Where do I enter it?

Open Proxy Manager Options

Click File | Proxy Manager Options in Outlook.

Click Register

Click the Register button in the Proxy Manager Options dialog.

Enter the license key

Enter the license key in the Register Proxy Manager dialog.

Manually entered From addresses

I am trying to manually enter an SMTP address to send from in the From dropdown in Outlook, but I keep receiving a non-delivery report.

Exchange Server does not allow sending from an arbitrary SMTP address. You can only send from your primary address or one of the proxy addresses assigned to the account.

Install Proxy Manager without user interaction

I need to install Proxy Manager on multiple machines without any user interaction. Does Proxy Manager installer allow that?

Download the zip file with the DLLs, copy the appropriate DLL to any folder, and register it with regsvr32.exe. Use ProxyMan32.dll for 32-bit Outlook and ProxyMan64.dll for 64-bit Outlook.

No elevated privileges are required because Proxy Manager installs itself in HKCU if it cannot be installed in HKLM. You can install it automatically with regsvr32.exe /s from a Windows logon script.

You can also copy the license key stored in the RegistrationKey value in HKCU\Software\AdvancedMessagingSystems\ProxyMan so outgoing messages do not include a footer.

REG ADD "HKCU\Software\AdvancedMessagingSystems\ProxyMan" /v "RegistrationKey" /t REG_SZ /d "xxxxxxx-xxxxxx-xxxxxx-xxxxxxx"

Increase the SMTP connection timeout

I am on a slow or high-latency connection and Proxy Manager frequently returns TCP/IP timeout errors when sending messages. Is there a way to increase the SMTP connection timeout?

Yes. Create a Timeout value, either string or DWORD, in HKEY_CURRENT_USER\Software\AdvancedMessagingSystems\ProxyMan. The value is in milliseconds. For example, to set a 60 second timeout, the value must be 60000. The default value without the registry value is 10 seconds.

Supported SMTP authentication

What kind of SMTP authentication does Proxy Manager support?

Proxy Manager supports OAuth2, Login, Plain, and CRAM-MD5 authentication. If your server does not require authentication, for example if it uses authentication based on IP address, you can leave the user name edit box empty and Proxy Manager will skip SMTP authentication.

Prevent users from editing display names

Our company would like to prevent end users from being able to specify arbitrary display names when sending through Proxy Manager.

Create a DWORD registry value named CanEditNames with a value of 0 in HKEY_CURRENT_USER\Software\AdvancedMessagingSystems\ProxyMan. User names will default to the display name of the Exchange account.

Multiuser and RDS registry defaults

I am installing Proxy Manager in a multiuser environment, such as Remote Desktop Services. Do I need to make every user configure Proxy Manager and enter the license key?

By default, Proxy Manager options are stored in HKEY_CURRENT_USER\Software\AdvancedMessagingSystems\ProxyMan. You can create a string registry value named RegistrationKey with the registration key in HKEY_LOCAL_MACHINE\Software\AdvancedMessagingSystems\ProxyMan. Since the value is added to HKLM rather than HKCU, it is visible to all local users and Proxy Manager reads it from there.