Selenium Grid can’t find Test Data

I got following Problem. The Selenium grid is running in a Docker Container and is connecting on a webserver which is also running in a Container. When running the tests, it seems like the webserver isn’t doing the same thing like when opening on my local computer. Do you know any reason this could have? i am getting following error “FacebookWebDriverExceptionTimeoutException : Must have more than one option in select”. The reason for this is, that the page is loading the content from the dropdown, which i want to select from, dynamicly. It seems like that there is the problem.

I tried mapping the data from the webserver to the selenium grid. I used curl out of the selenium container to check if there is any data in the dropdown, but there isn’t.