When preparing to send a proposal for a job, a message came up from Upwork that said, "You do not meet all the client's preferred qualifications. You may still submit a proposal, but the client will see that the proposal does not meet the following criteria: Upwork Hours: 1". I don't understand what this means and why I would not be qualified the position.
Just ignore that warning.
If you're able to do the job, then apply.
Upwork job applications have DEFAULT settings that require certain minimum number of hours or minimum job success scores and such, and clients often don't even realize that those settings are there. Many clients don't care about those requirements.
And even if a client intentionally sets a minimum requirement, most of the job applications she receives are pretty terrible. YOUR application will stand out and she will appreciate your application, even if it technically doesn't fit a requirement.