You can check on your refund status by following the links below.
If accepted by the IRS use the federal tax refund website to check the refund status - https://www.irs.gov/refunds
If accepted by the state use this TurboTax support FAQ to check the state tax refund status - https://ttlc.intuit.com/questions/1899433-how-do-i-track-my-state-refund
After the tax return has been accepted by the IRS (meaning only that they received the return) it will be in the Processing mode until the tax refund has been Approved and then an Issue Date will be available on the IRS website.
See this IRS website for federal tax refund FAQ's - https://www.irs.gov/refunds/tax-season-refund-frequently-asked-questions
Unfortunately, only the IRS would know why your return is still processing. TurboTax does not get any information about your return or refund once your return is accepted.
Since it has been over 21 days you can also call the IRS for information, but it may take some time to connect.
The IRS telephone number is 1-800-829-1040, and they are available from 7 a.m. – 7 p.m. Monday thru Friday. The best time to call is early in the morning.
-follow this link for additional information-
Where's My Tax Refund? How to Check Your Refund Status ...
