Reason 1: Bookkeeping gaps
The single most common reason a file stalls is that a lender cannot read it. Mixed personal and business accounts, months of missing categorization, or financials that do not match the tax return all force an underwriter to guess, and underwriters do not lend on guesses.
The fix is not fancy. It is clean, current books: separated accounts, monthly reconciliation, and statements that line up with what you filed. When your numbers tell one consistent story, the rest of the application gets easier.