If you're using Mendix 4.4.x, it's a bug in the Mendix Runtime, which incorrectly reports the status. So your application is likely just 'running', it's only incorrectly reported to the outside, messing up the monitoring checks.
The 'feut' state is a state which should never be visible from the outside, because the Runtime is only in this state when it's 'unborn' and not able to react to anything yet. The first thing before requests can be handled is the switch from feut to 'starting'.
So, this is obviously a bug. This bug was introduced in Mendix 4.4.0 and fixed in 4.4.3, so you should not see this anymore when using 4.4.4. As you're reporting it on 4.4.4, please doublecheck?
'feut' is a state where the server has not been correctly started. It's a highly unlikely situation and I couldn't tell you what happened in this case. Can you tell us some more about the your on-premise situation and how you configured things?
We actually encouter the same error message on one of our local deployments. The funny thing we can actually log in to the application and everything seems to be working fine.