IPad displays "not charging" message when connected to a USB power supply?

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New member
What could be the reason an IPad displays "not charging" message when connected to an USB power supply?
It is actually charging and after some time, it gets fully charged
An Ipod when connected to the same power supply, displays the correct message.
Is there a firmware problem or is the IPad hacked?
Photos can be provided on request
 
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