failed to find target with hash string android-23

Solution 1:

In my case, clearing caché didn't work.

On SDK Manager, be sure to check the box on "show package descriptions"; then you should also select the "Google APIs" for the version you are willing to install.

Install it and then you should be ok

Solution 2:

In Android Studio File -> Invalidate Caches/Restart solved the issue for me.

Solution 3:

The answer to this question.

Gradle gets stupid from time to time and wiping out the cache is the only solution that I've found. You'll find a hidden .gradle folder under your user home folder and another one wherever the checkout location is for osmdroid.