Share Query Layer with other user

Hello,

I have a problem with query layers.
I created some SQL queries for our new project to use them as query Layers in ArcMap. Therefore, I have made some queries on our central oracle database. Now I see this queries as event layers (boreholes) in my map. In the next step I saved my event layers as layer package to share them with other user.

Every user should be able to use these layer package and to see my SQL queries/event layers on his own ArcMap/PC.

My problem is, that the users have a red exclamation mark on their layers and they are not possible to see the event layer, despite existing database connection.

What's wrong??

Thanks
Maik