My Phone will not recognize USB connected
First of all, please make sure that you have latest Samsung USB driver installed on your computer, if not please update it or download latest version from this page.
Second, make sure that USB cable is working properly.
Third, if USB cable is ok, driver is up-to-date and you still won't able to connect, then type in your Phone app this string *#7284#and check the option MTP + ADB, press save and reset. This should solve connection issue.


P.S. If appeared *#7284#  "service screen" is different which means you can't see the MTP + ADB option please post the screenshot here.