Change Apple ID password but does not work after change?

Are you following Apple's criteria for a password? From the first link Iafeef posted.

When you create a new password, keep the following in mind:

• Your new Apple ID password must contain at least eight characters, a number, an uppercase letter, and a lowercase letter. 
• You can't use spaces, the same character three times in a row, your Apple ID, or a password you've used in the last year.

Hey there,

i don’t think I understand your problem well but See this Article’s might help you:

☞ Change your Apple ID password - Apple Support

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☞ What to do after you change your Apple ID or password - Apple Support