This is actually a duplicate of this SO question, but since my problem is still not solved I thought this is the correct way to find a solution for my problem:
I have a fluid domain (cube) and a fluid object (uv sphere) inside it (guess that is the standard). Without having changed anything big my fluid object or rather just the fluid is being stretched to one side of the domain boundary. Take a look at the picture:
In the other post the accepted answer is
"The normals of the inflow object are inverted. Flip or recalculate them."
which I tried but that did not help. Unfortunately I am a super beginner and after hours of trying don't know how I could solve this myself. Thanks.
Here is the .blend file.