I seem to have lost the WeMod icon that used to show up as active in the system tray (bottom right corner). The name of the application shows when i mouse over it, but the icon can’t be seen. I’ve tried uninstalling and reinstalling, but is still doesn’t show up. Any suggestions, please?
This is most likely a Windows issue and not a WeMod issue 
The best suggestion and least technical would be to uninstall and re-install WeMod.
Make sure you know your login beforehand as you’ll need to log back into your account 
Welcome to the community @Kashegan.
Missing system tray icons is indeed a known Windows issue, as @Instinct mentioned, that has been around since at least Windows 7 up to Windows 10 today.
Check your notification settings (Win 10):
- Right-click the clock on your task bar.
- Click “Customise Notification Icons”. A window will pop up.
- Make sure the slider underneath the “Notifications” header is set to on.
- Scroll down the “Get Notifications From These Apps” header in the same window, locate WeMod.
- Make sure notifications from WeMod are turned on.
If these settings are already on or if turning them on doesn’t immediately fix the issue - restart your computer.
I had this issue before with a different (non-WeMod) software. Restarting the computer fixed it for me at that time.