I can't save in admin panel

Hi everyone,

Today, i have an issue about save in admin panel.

When i go in my directory theme admin panel > Theme setup i can’t save anymore using the save changes button.I am redirected to a 404 page which doesnt exist.

Into all my tabs, button “save changes” doesnt work. General setup,page setup, content setup …I can’t save and so don’t make any changes for my website.

I have a looked at my htaccess file for redirection and php.ini but i don’t know if that is the solution to my issue.

Just a little info, my hoster has changed my old server to a new one and my Ips adress is not the same.

Thank you everyone,
Have a nice day,
Best regards