Mobile app SSO attempting to log in to former company's SSO

[SarahGillespie]

I am the admin on our enterprise account. We manage our mobile apps through Intune. We have a user that worked for a different company that is trying to log in to Zoom using our SSO on the Zoom app that was installed from our Intune company portal. Even though they have entered our domain in the SSO screen and it looks like it starts to authenticate with our company, they are presented with a screen saying it's connecting to the former company's Office 365. We have tried removing all credentials related to the other company that are saved in the device and have uninstalled and reinstalled the Zoom app from our Intune Company Portal. 

Any suggestions on resolving this issue would be greatly appreciated.