Problems related to the file could not be opened or the application is not installed:
First Solution:
Use Google Chrome when you download it, and don’t close the app while it downloads the app.
Second Solution:
Stop Saving data in Google Chrome browser:
Third Solution:
MAke sure the download is completed 100%, which means for example if the size of the app is 37 MB and it only got to 10 MB then this means you have a network connection problem.
استخدم تطبيق مدير التنزيلات تستطيع من خلاله تحميل الملف كامل، تستطيع حذف البرنامج بعد تنزيل التطبيق.
Use Advanced Download Manager ADM to make sure you can download the whole file.
Fourth Solution:
Restart the phone and then download the file again
Fifth Solution:
This step may be different from one phone to another but try to get to Device settings > Applications or Application manager > Tap on More > Show system apps > Find and select Download Manager > Storage > Clear data