New Product Option submit redirects to dashboad

I created an Option field for Country and added 100+ options to it for various countries. This worked fine. However, when I go into the product to add the new options (and clicking Save or Save+Close), it returns to the Joomla admin dashboard and does not save the new options with the product. It accepted three options, but fails when I try to add any more, returning to (administrator/index.php) without any error messages. Error reporting is set to maximum, but none are displayed and nothing shows up in the server logs... Any ideas what is going on here?

Hello Chad,
This because the maximum fields allowed to upload on your server settings. When you add too many options value to product, the fields on the form exceed this setting on server so the form can not be submitted. To solve it, please increase value of this variable: max_input_vars
Hope that my answer will help.
Sincerely, Giang