The Atlas has a globe for three bodies: Earth, Mars and the Moon. An address for anything else, such as /projects/locations/jupiter, does not fail. It quietly shows the solar system view instead, with no message and no error page, so a mistyped or out of date link looks like it worked.
If you arrived at the solar system when you expected a globe, the name in the address is the thing to check first.
Why nothing tells you
The address accepts any body name and only those three switch the page into globe view. Anything the page does not recognise leaves it in its starting state, which is the solar system. There is nothing to distinguish a name that was never valid from one you simply typed wrong.
Capitalisation does not matter. /projects/locations/MARS and /projects/locations/mars both open Mars.
Orbit is a place, but not a globe
Projects can be placed in orbit rather than on a body, and those show in the solar system view. Orbit is not a body you can open, so there is no /projects/locations/orbit. See Projects placed in orbit are not counted on any body.
Older links still work
An address of the form /projects/locations?body=mars is still understood. The page rewrites it to the clean form as it opens, so a bookmark from before keeps working and gives you a tidier address afterwards.
The reliable way in
Open the Atlas from Explore in the sidebar and select a body from the solar system view. That guarantees a name the page recognises, and it is also how you get back: the Solar System button in the top left of a globe. See Getting back to the solar system on the Atlas.