can not make changes to my website using css file

[netpositiveradio]

Hello,
I can not make changes to my website using the css file. I can upload the changes to the server successfully but when viewing the website, they don't take effect. I have even deleted the css file entirely for the past 2 days and the website displays as if the old file is still there. When I make changes to the index.html file, those changes do take effect. What is the problem and more importantly, the solution.
Thank you.

[karl94]

You have CloudFlare active on your account, be sure to activate the development mode from the AlterVista control panel or to clean its cache when making changes to your website.

[netpositiveradio]

Thank you!