Fix Anamaya - wordpress website technical issues

I need you to fix the technical issue of the following website: [login to view URL] Currently the technical issues are: 1. Hundreds of 403 errors 2. Hundreds of 404 errors 3. Something wrong with .htaccess file because it cannot be edited to add 301s 4. Code or plugin must be added to automatically redirect deleted tag pages, category pages, etc so no more "file not found" errors of this type will appear.