Can't install my apk after keystore signing

Before I sign my apk in the publishing settings, I have no problems with installing my game in any android device. I made sure the install location is set to Automatic as it was giving me problems before. After looking through the internet I came across some people saying that it could be due to java jdk, so I go the latest version and pointed the unity towards that location but still no results. Can anyone tell me whats going on?

are you installing with build and run?
are there any error messages?
if you remove the old installation, does it then work?

No, I build it first then copy it to my android device. I don’t get any error messages. I just tried removing the old application and do a fresh installation, it worked. But why? isn’t that a problem?

same problem ?!
i test at another new empty project and still problem