If you can not add products to the shopping cart, First of all, you should make sure that the cookie is open. And then please clear the cookie in the browser.
If you are using IE browser, first find out the "Tool" on the menu of the IE browser, and you will see a "Internet option", open it, there is a button "clear cookies", click it, and the cookie will be cleared as well.
If your browser is Firefox, click the "clear the privacy data", which is in the tool also, make sure the "cookies" is checked, finally click "clear the privacy data at once". It will be OK.
According to the Safari browser, open the "edit"and then "Restore safari… ", make sure the "clear all the cookies" is checked. And then click the Restore button.
If you have any other questions, please contact us. service@safebuyfromchina.com