I mailed out my taxes on March 17. They still haven’t been accepted by the IRS, what can I do to see if they received them?

you get no acceptance e-mail for mailed returns. 

if you are due a refund you can check the WMR site

https://sa.www4.irs.gov/wmr/ 

or call the IRS. However, it is possible your return is at the IRS in an unopened mail bag.

 

If you didn't do so, in the future if mailing your returns, use a tracking service so you'll know if the IRS got it.

 

If you are due a Federal refund, here are some tips when using the IRS "Where's My Refund" tool mentioned above.

 

• Be sure you enter the correct tax year, SSN and filing status.
• Be sure you are using only the Federal refund amount.   Do not include any state refund or any total refund or net refund (Fed and State) that TurboTax may have provided on a summary screen.  
• Look at your actual Federal return to get the Federal refund amount to enter, i.e., your Form 1040, Line 35a.