This is the final Process of fixing certificate error when install app or game on java or symbian mobiles.
This methods will support all over this similar devices or symbian and java etc devices.
Step- 1
Open mobile
Step- 2
Go-To control pannel | Ctrl pannel
Step- 3
Click "Settings" and open it
Step- 4
Open "General"
Step- 5
Open "Date and time"
Step- 6
Click "Date" and set to the year of: 2014 / 2010 / 2016 / 2018 [If not work 2014 so, try anoter dates.] The years actually work based on the app or games basically the softwares creations dates instead.
Just set the dates aren't fix everythings! And this "step- 6" you need to setup and after process instead of "step- 6".
Follow step-by-strp
After edited dates than resterts { Just Switch of the mobile and again Switch on / Off and on } the phones onec, if not work next!
Step- 7
Go-To "Office" than- open "File Manager" | Open File Manager
Step- 8
Download the "Norton Security" and "Room Patcher" app than "Install" these applications [ There are huge of this types of applications available on the marketplaces. ]
Norton Security - Download
Rom Patcher - Download
Install with the provided linked links or install it's yourself!
Step- 9
Open Norton Security app and open/click "Options/Menu" than open "Antivirus" and Click "Quaratine list" than remove all/delete all listed lists. After deleted/removed all quaranline lists exit of this apps.
Don't avoid any of steps! [You will finds these apps on your application sections, not control panel. I moved this apps to control panel!]
Step- 10
Open Room Patcher app than open Options/Menu and go-to all patches- apply all OR go-to advanced- apply all.
( You can select or click one by one of these options) {Just need to apply / Tick-mark these }
Finally
Congratulations😎🎁Now, you can install any of apps or games on your mobile. {Just avoid unsupported games, which is not possible to install or not for your devices.}