Should I use the word successfully in pop-up messages?

The workflow:

User clicks on a button that triggers some action. On top of the screen appears a small pop-up that informs about the result of an action (successful or not).

For example:

New files added successfully

New files weren't added

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Files deleted successfully

Files weren't deleted

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Users invited successfully

Users weren't invited

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Should I use successfully each time? Or just for short sentences denoting small actions?