"There was an error sending the request! (403 error)" ~ cmsbuilder_3_55_build2297

Hello, 

Hope your all well

I am using cmsbuilder_3_55_build2297
My cpanel PHP version is set at 7.4

I have issues manipulating an editor aka

I can add a new editor
i select Multi Record
Its when I am >>> CMS SetUp > Editors > and click modify and i try to add a field..... i click save only to get an error "There was an error sending the request! (403 error)"

I have being to my cpanel and gone to Databases, and assigned all User Privileges.

Any thoughts on what i need to change to not get the 403 error.

Cheers

Kenny