Patch Project Tasks Doesn't Work

We use Project for the web and I have developed a canvas PowerApps application. I was able to disply Project tasks, but when I patch a task either nothing happens or I receive a "Network error".

Could you please advice how I can update tasks, particularly Remain and Complited hours?

Patch(
    'Project Tasks',
    LookUp(
        'Project Tasks',
        'Project task ID' = ThisItem.'Project task ID'
    ),
    {
       'Effort Completed (Hours)': Value(ThisItem.'Effort Completed (Hours)')
    }
)

Thank you in advance

Slava