* Reboot the phone: Rebooting the Android phone could help clear OS errors that might have occurred. Check the SD card for errors and fix if required ( See How to fix / repair corrupt memory card, SD card or USB drive ).
* Format the SD card: In extreme cases, move the contents on the memory card to a different location then format it.
* Wipe the phone: In extreme cases, wiping the phone could resolve this issue. You could either do a factory reset under Settings or data / factory reset in recovery mode.
* Ensure to uninstall unneeded apps to create space. Uninstall any apps you don’t need. (See this experimental post on How to increase primary partition (internal storage) on an MTK (like Tecno) Android )
* Double-check the apk file: Check to be sure the apk file was properly copied / downloaded and is the correct size.
* Reset permissions: Try resetting app permissions (Settings > Apps > All > Menu key > Reset application permissions ) Uninstall any previous versions on the same app currently installed on the Android phone.
* Change Installation location: You could toggle application install location between phone memory, SD card and automatic. Ensure that the SD card in not mounted / connected to a PC Avoid installing unsigned apks or changing apk file names prior to installation.