How can i operate the object on the popup window

when i click the hidden button on the bottom page ,the popup window appeared,the popup window blocking a part of the bottom page.
my issue is the button on the popup window can be located sucessful,but can’t use the .click(),when use the .click(),it’s no response
however,when the popup window appeared,the hidden button can be located and use the .click() is ok

(appium for windows 4.1.16+python2.7)