Only one user email address can be part of one organisation; therefore is unable to see two organisations at the same time with the same user.
If you're managing two organisations, you will have to create one user for each of them with a different email address per organisation.
🤓Tip: A suggestion to view both organisations on one device, you can log in with one user on a browser, open another browser in incognito mode by pressing CTRL + SHIFT + N, and use it to log in with the second user.