For OpenText Integration, a Tenant ID, Client ID and Client Secret are required to send email. An overview of their messaging API can be found at Messaging | Developer | OpenText
On the Admin Center navigation menu, select Apps and click Add.
From the Add list, select Add new standalone app.
In the Display name box, type a display name for your app. Users will see this name when they access the app.
In the App name box, type an internal name that uniquely identifies your app.
In the Version box, type a version number for your app, for example, 1.0.
In the Description box, type a description for your app.
From the Tenant list, select the tenant created above.
Click Save to generate both public and confidential credentials for the app.
Click Copy all to copy all the values shown in the panel to your clipboard.
Paste the copied information into a text editor and save the file to your file system. Keep your configuration files confidential and never store them in a public repository. The client secret values are not stored in Admin Center. You will not be able to retrieve the client secret value again. If you lose your client secret value, you have to regenerate a new one.
Click Console and select <organization name> <region> combination.
On the Admin Center navigation menu, click Apps.
On the Apps page, click the required app.
Click the App navigation menu, click Service clients.
Use Copy button to copy the client ID.
The client secret is only generated once when the app is created. If you have misplaced your client secret, select Regenerate client. This should give you a new client secret.
OpenText utilizes OAuth2 when authenticating with their services. Their Authentication service can be hosed in one of many regions. All regions can be found at Authentication | Developer | OpenText.