Mouse over your Hello menu item and Click "Settings"

Look down the tabs on the left of the page and Click "Email (SMTP & IMAP)"

Click this dropdown to see your options for Predefined Settings and choose Custom to connect to Exchange servers

Custom
Gmail (Auth Process)
iCloud
Outlook via OAuth2

Enter data into all of the fields. This information is obtained from your email server administrator (not ClientTether).

Predefined Settings:    
Custom
Gmail (Auth Process)
iCloud
Outlook via OAuth2

After entering appropriate information is all the field,,, Click "Save Settings"

Watch for Messages in the upper right of the screen.

To see if this is successful Click "Test SMTP Send".\
Watch for system messages in the upper right of the screen that indicate success or failure.

Watch for system messages in the upper right of the screen that indicate success or failure.

The most common cause for failure is a mistake in entering the data in each field. Verify you have the right data

The second most common issue is that SMTP is NOT turned on in the email service.  For security reason many Email Administrators do not turn on SMTP features for an email address by default.  \
Only your email administrator can help answer this concern.  Make sure they have turned on: IMAP, POP and SMTP for you email address.

When your credentials are properly entered and all services are turned on, then you should see a Success message.

Configuring Custom SMTP and IMAP Settings in ClientTether Account (including MS Exchange)