How can I overcome this problem?
Samsung Galaxy TabS - Android 4.4.2
HTC M8 - Android 5.0.1
The two devices have the same problem.
Your device is not rooted. To see what Rooting is and how to go about doing it:
Once you have rooted your device, you will be able to access the Super User state of your device (SU). Just be aware that rooting could brick your device if done incorrectly, as could and tampering with files in the root directory.
Thank you for your interest in this question.
Because it has attracted low-quality or spam answers that had to be removed, posting an answer now requires 10 reputation on this site (the association bonus does not count).
Would you like to answer one of these unanswered questions instead?