Some problems installing sites into my multisite network

Hi there guys!

I asked some help turning my single site to a multisite and I made the stuff...all right! :slight_smile:

Then, I tried to install the first single site for my network ( and it went wrong I guess. Cannot access the frontend, and not even the backend.

I installed a theme later, for make it available to all the network...and it does not appears.

Thank you for your help in advance, hoping anxious your words to start using all your amazing plugins for multisite networks :wink: