If your screen is getting unresponsive in some specific places don't worry too much, you are not alone. It's a known issue that has been affecting different devices, brands and Android versions. The usual "dead" spots are placed on the four corners, the middle of the screen or some letters when you open the keyboard. Thanks to the community feedback there are some simple fixes that, most likely, will solve your problem. Check them out and tell us if they did the trick for you. Please, feedback is the key 
Interference. If you are using a case take it out, reboot your phone for a fresh start and try again. There's a chance that it could be interfering with some sensors in your phone.
Third party apps. For most people with this problem the cause was a conflict with an app. These are some of the culprits.
- Facebook Messenger. The conflict is related to the chat heads. Disable this app temporarily and see if the problem persists. For a few users just disabling the chat heads did the trick.
- Live wallpaper. Change your live wallpaper for an static one that came preinstalled in your phone. Reboot and see what happens.
- Clean Master. There's an special feature called "iswipe" that has been causing different screen problems for some users. Disable or, even better, uninstall this app. It's possible that you'll need to uncheck it first in settings - security - device administrators.
- There are a few reports about Samsung Pay or Droid Optimizer causing screen issues that stopped after disabling any of these apps. There's not much feedback about these apps though, but still worth a try.
Safe mode. This process will temporarily disable every app that didn't come preinstalled in your phone. If the problem doesn't appear while your phone is running in safe mode then it means that you have a tedious task ahead. Reboot your phone to exit safe mode and start disabling, one by one, your apps until you find the culprit. You should start with apps that you downloaded or updated right before the problem started and any app with fancy screen features like bubbles, swipe or lock options. Just be aware that some of the apps listed before do come preinstalled in some phones/brands, so they will run even in safe mode!
Developer options. If you're still reading this there's a big chance that nothing worked for you and maybe your phone has a hardware problem. There's an easy way to get visual feedback every time you touch the screen so you can check if there are any real dead spots. You need to have the developer options enabled so if they are still disabled go to settings - about phone - scroll down and tap 7 times on the Build number until they open.
Open the developer options, scroll down to the "input" section and switch these options on:
Show touches. You'll see a visual cue on the screen when a touch is registered. It will recognise when you swipe around painting the whole path.
Pointer location. The coordinates for the last touch will appear on your status bar.
Now, tap & swipe over those places where you are having issues. If you don't get a visual feedback (broken line when swiping) or the coordinates don't change, there's a big chance that you need to visit a repair shop or make use of the warranty. You can see in the screenshot how these options work
When you finish the test remember to switch them off and you can disable the whole developer options with the toggle top right of that screen.
Nothing worked. If you can't manage to fix the problem there's always the last resource. Make sure to backup everything you don't want to lose and hit factory reset. If you're going to send your phone to the shop they are going to do it anyway, so ....
Good luck .
Interference. If you are using a case take it out, reboot your phone for a fresh start and try again. There's a chance that it could be interfering with some sensors in your phone.
Third party apps. For most people with this problem the cause was a conflict with an app. These are some of the culprits.
- Facebook Messenger. The conflict is related to the chat heads. Disable this app temporarily and see if the problem persists. For a few users just disabling the chat heads did the trick.
- Live wallpaper. Change your live wallpaper for an static one that came preinstalled in your phone. Reboot and see what happens.
- Clean Master. There's an special feature called "iswipe" that has been causing different screen problems for some users. Disable or, even better, uninstall this app. It's possible that you'll need to uncheck it first in settings - security - device administrators.
- There are a few reports about Samsung Pay or Droid Optimizer causing screen issues that stopped after disabling any of these apps. There's not much feedback about these apps though, but still worth a try.
Safe mode. This process will temporarily disable every app that didn't come preinstalled in your phone. If the problem doesn't appear while your phone is running in safe mode then it means that you have a tedious task ahead. Reboot your phone to exit safe mode and start disabling, one by one, your apps until you find the culprit. You should start with apps that you downloaded or updated right before the problem started and any app with fancy screen features like bubbles, swipe or lock options. Just be aware that some of the apps listed before do come preinstalled in some phones/brands, so they will run even in safe mode!
Developer options. If you're still reading this there's a big chance that nothing worked for you and maybe your phone has a hardware problem. There's an easy way to get visual feedback every time you touch the screen so you can check if there are any real dead spots. You need to have the developer options enabled so if they are still disabled go to settings - about phone - scroll down and tap 7 times on the Build number until they open.
Open the developer options, scroll down to the "input" section and switch these options on:
Show touches. You'll see a visual cue on the screen when a touch is registered. It will recognise when you swipe around painting the whole path.
Pointer location. The coordinates for the last touch will appear on your status bar.
Now, tap & swipe over those places where you are having issues. If you don't get a visual feedback (broken line when swiping) or the coordinates don't change, there's a big chance that you need to visit a repair shop or make use of the warranty. You can see in the screenshot how these options work
When you finish the test remember to switch them off and you can disable the whole developer options with the toggle top right of that screen.
Nothing worked. If you can't manage to fix the problem there's always the last resource. Make sure to backup everything you don't want to lose and hit factory reset. If you're going to send your phone to the shop they are going to do it anyway, so ....
Good luck .
Facebook
Twitter
Instagram