Sub-directory Site created but not found

Hey guys,

thanks in advance for your help. I’m currently stuck with this issue and have no idea how to solve the problem. I give you the steps I went through and what exactly my problem is. The goal is to create a Multisite-Network with sub-directories.

1. I go to ‘My Sites’ > ‘Sites’ > ‘Add new’
2. I enter the subdomain (‘en’), title and admin mail
3. Website is successfully created and shows up on my ‘Sites’ screen unter ‘My Sites’
4. When I try to access the dashboard of the newly created site I get a redirect error (Chrome says ‘ERR_TOO_MANY_REDIRECTS’)
5. When I try to access the site itself I get it without any css and it loads extremely slow (Due to the redirect error on wp-admin I cannot activate a theme or anything)

If you need any further info just tell me. Thanks so much!