Using admin panel, I can't save the home

Using Admin Plugin rc7 and antimatter, I can't save the home.
I can add new pages. I can save these pages.
I can copy the home, but I can't save the home copied neither.
It says 403 error.
I checked blew, it does't work.
http://learn.getgrav.org/troubleshooting/forbidden

There is any idea ?

Quick question - are you using PHP's default webserver? Locally or on a server?

I'm using php5.4 on a hosting service server.

Is this server running Windows? Is this IIS or Apache? If Apache but on Windows, you will need to change the param separator to use ; instead of : as there is a problem with : in URLs with Apache on windows.

I don't think so.
Configuration - PHP Info says host : x86_64-redhat-linux-gnu

"Troubleshooting 403 Forbidden" does't work for me.
I can save adding pages. It does't make sense.

I use skeleton package Twenty Site on the same server, I can save Twenty Site's home.

What is the name of the folder of the home page? did you change it from 01.home to something else?

Also maybe you can zip up your site for me and put it on dropbox.. send me a Private Message with the location to the zip and I'll try to reproduce your problem locally.

No. I did't change the name of the folder.
I get grav-admin-v1.0.0-rc.5.zip from http://getgrav.org/downloads.
I install manually.
It happen.

Then I install grav-skeleton-onepage-site-develop.zip manually.
as you write on https://github.com/getgrav/grav-skeleton-onepage-site.
This case it works.
and install antimatter and uproad 01. home also works.

well what I did to test was to:

1) Download the release of the onepage skeleton: https://github.com/getgrav/grav-skeleton-onepage-site/releases/download/1.0.1/grav-skeleton-onepage-site-v1.0.1.zip

2) Install admin and plugins via: bin/gpm install admin

3) Created an admin user with bin/plugin login newuser

4) Logged in to admin and was able to open and save the homepage:

2015-11-30-21-da4cq

thanks rhukster.

but why grav-admin-v1.0.0-rc.5.zip does't work ?
what's the difference between Grav-admin and onepage-site?

something worng at grav-admin's pages/01 home/default.md

Now I delete 01.home/default.md by ftp.
Then I can make new default.md by admin plugin, and save 01. home.

I'm so sorry.
I found the cause.
Web Application Firewall deny some Markdown code.

So I add some lines on .htaccess like blew.
SiteGuard_User_ExcludeSig sqlinj-22 (it's depend on WAF softwear)

Thanks rhukster, taking your time.
I really appreciate what you've done.

no worries, glad you got it sorted.