Hello the password is ok, since it is on the MacBook with Adobe Acobat to open is. At 3 tries to enter the password comes then invalid password, which can not be true that it is on the ipas and iphone with the App Foxit Pdf open. very strange. Greeting Wolf
Please try to open any other secured PDF on your mobile application and check if it opens.
Do you get any error message when you try to open PDF on your mobile application? If yes, please share the screenshot of the error message.
What is the dot version of Adobe Acrobat Reader installed on your device?