title: Cannot install signed apk to device manually, got error "App not installed"
body: <p>I'd like to publicate my app to GooglePlay but first i would like to do a last testing with the signed apk to ensure that all of the used API keys are working correctly with the release version (GMaps, Facebook, etc)</p>
  
  <p>So i just <strong>made a signed version of my app with our release key</strong> and when i try to install the app to the device <strong>i got an error:</strong></p>
  
  <p><a href="https://i.stack.imgur.com/ck3uM.png" rel="noreferrer"><img src="https://i.stack.imgur.com/ck3uM.png" alt="enter image description here"></a></p>
  
  <p>I have tried to copy the apk to the device and <strong>install it with an apk installer app.</strong></p>
  
  <p>Strange thing is when i do the same process <strong>with debug signing key, all is well, I can install and run the app.</strong></p>
  
  <p>Here are the <strong>steps of the procedure:</strong></p>
  
  <p>I select the <strong>release key</strong>, type password.</p>
  
  <p><a href="https://i.stack.imgur.com/bWk81.png" rel="noreferrer"><img src="https://i.stack.imgur.com/bWk81.png" alt="Here are the steps of the procedure:"></a></p>
  
  <p>I do <strong>select release build type</strong> instead of debugging</p>
  
  <p><a href="https://i.stack.imgur.com/joqXA.png" rel="noreferrer"><img src="https://i.stack.imgur.com/joqXA.png" alt="I do select release build type instead of debugging"></a></p>
  
  <p>Just in case <strong>i also defined in the gradle file the signing keys</strong> but I must admit i dont know is it necessary.</p>
  
  <p><a href="https://i.stack.imgur.com/DZ6uM.png" rel="noreferrer"><img src="https://i.stack.imgur.com/DZ6uM.png" alt="Just in case i also defined in the gradle file the signing keys but I must admit i dont know is it necessary."></a></p>
  
  <p>I tried like 7 seven times now so i assume this problem is <strong>not just a 
  mistyped password</strong>, also <strong>I can make this work with the standard debug android signing key.</strong></p>
  
  <p>Please help if you can.</p>