Get a copy of the appraisal immediately and review it for accuracy. Call the agent that sold you the property and ask for current comparable sales and rents. Appraisers are very conservative these days and occasionally they make mistakes. If you find significant problems with the appraisal, it may be worth pointing them out to the lender. They may send the appraisal back for review if the errors are egregious or order a second appraisal, which you will have to pay for.
If the appraisal is accurate, you will have to decide if you want to risk putting all your reserves into the refinance. Operating a rental propertal property without cash reserves would keep me awake at night, unless I could cash flow a major repair.