Multisite on Plesk server not working (correct install wordpress)

General information for the website: Multisite, Wordpress, Plesk Server
Description of requirements/features: Hi,

We have setup a whole multisite and on the website all is good and installed correct.

On server side we activated multisite and all looked good. But...

Activation emails for the sub sites are received, but the activation link (after click) shows up with broken css ondefault theme.

We are running on a dedicated Plesk server. Can anybody help us?

Thanks!
Extra services needed: Domain, Hosting
Specific technologies required: Plesk Server, Wordpress
Similar urls: mondiadox.com
Extra notes: General information for the website: WPMU Multisite, Install wordpress correct. But subdomains are not showing correct
Description of every page/module: Hi,

We have setup a whole multisite and on the website all is good and installed correct.

On server side we activated multisite and all looked good. But...

Activation emails for the sub sites are received, but the activation link (after click) shows up blank / broken css.

We are running on a dedicated Plesk server. Can anybody help us?

Thanks!
Description of requirements/features: Make subdomeins work correct on this plesk server.
Extra services needed: Domain, Hosting
Specific technologies required: Plesk server, Wordpress Multisite
Similar urls: mondiadox.com
Extra notes: