SCC has now started to retired the mobility portal and replaced this with MyApps.
to access these browse to myapps.microsoft.com and sign in with your SCC account (same account you currently use to access D365)
Once signed in you will see a list off applications you have been granted access to,
to access the PO System or overtime simply click on the icon, and you may be prompted for the username and password again, this again is your SCC one.
any problems please email it.support@scc.com