App downloads completely, but doesn't install

[AC Question]

Am using a brand new phone with 2gigg ram and 8.76 gigg available now,but after I download certain apps from the store ,it fails to install ,displaying error downloading, error 504.....even when the application is downloaded from a forum or is sent to me,while its installing,the same result happens ,I have cleared both Google play services and Google play store and forced stop too,but the same result ...I have rebooted my phone countless times, but still same result.. Please what can I do

 

[dpham00]

I would try to backup any important data and do a factory data reset