Hello first of all together,
I am currently working on my own MLO. This is the second one I have ever started. The first one I had the same problem, but I thought it was because of mistakes I made.
Now I have started a new one, but I have the same error again.
Below I have attached several screenshots.
In Codewalker the interior works without problems, but as soon as it is on a server it is not loaded.
On the server:
If you need any more screenshots or information, just tell me I will upload them.