The most likely cause for the one-X Portal for IP Office service not working and remaining yellow in the platform view of the services is a password mismatch.
The mismatch is between the EnhTcpaService service user in the IP Office system's security settings and two of the providers within the portal configuration (the Default-CSTA-Provider and the Default-DSML-IPO-Provider). This password mismatch causes the IP Office to automatically lock the EnhTcpaService user account.
With the Unified Communications Module, the portal service assumes that the IP Office is using the default password.
To reset the portal and IP Office passwords:
1.Change the portal provider passwords to the new, strong password:
a.Login to the portal services administrator menus. You can do this by logging in to the portal server's Web Manager menus, clicking on Applications and selecting one-X Portal.
b.Click Configuration and select Providers.
c.Set the Provider Name field to Telephony (CSTA).
d.Click on the 
edit icon next to the listed provider.
e.Set the Password and click Save.
f.Set the Provider Name field to Directory (IP-Office) and repeat the process.
2.Stop the one-X Portal for IP Office service:
a.Login to the server's web manager menus.
b.From the Solution page, click on the 
icon next to the portal server and select Platform View.
c.Stop the one-X Portal service. Wait until the status icon changes to red.
3.Change the password of the IP Office EnhTcpaService service user:
a.Login to the IP Office system's Web Manager menus.
b.Click on Security Manager and select Service Users.
c.Click on the edit icon for the EnhTcpaService user.
d.Set the Password to the same as was set for the portal providers above and click Save.
e.Change the Account Status back to Enabled.
f.Click Update.
4.Restart the one-X Portal for IP Office service:
a.Select the platform view for the portal server again.
b.Start the one-X Portal service. Wait for the status icon to change to green. This can take up to 5 minutes.