Many users face this problem when they change their skin like that:
One of these reasons:
1-There's 2 files with same name in your Ranked Gaming Client=>Skins
example:
Solution:
Delete one of this 2 folders or rename it.
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2-the images inside the skin that you want to use it maybe corrupted or deleted try to check your Ranked Gaming Client=>Skins=>(Requested skin)=>Images=>
example:
Solution:
Delete pics with same name or redownload requested skin.
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3-you've extracted the skin in another skin folder
example:
Solution:
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Re-extract the requested skin in the correct path(Ranked Gaming Client=>Skins)