I filed online via TurboTax and mailed my payment two weeks ago but the check has yet to clear. What should I do?

[br5656]

This is the first time I did not send the payment with a tracking number/certified mail. I am afraid that it is lost in the mail and I will get penalized.

[Mike9241]

you have two options wait some more to see if it's cashed or use the IRS website to make an online payment which would stop the accruing of penalties and interest. if and when you receive a penalty notice, you can write back to the IRS explaining the situation and requesting abatement of penalties, By law, interest can not be abated. It's totally at the discretion of the IRS as to penalty abatement

https://www.irs.gov/payments 

if you decide to make the online payment you could then stop payment on the check.

here's from the IRS website about stop payments

https://www.irs.gov/taxtopics/tc206 

Stop Payments
A dishonored check penalty isn't assessed on checks or other payment instruments for which you placed a stop payment order. If you're assessed a penalty, please send a copy of the stop payment request along with your penalty relief request to the service center address listed on your Letter 608C

[Affordabletaxes2021]

It took the IRS 8 weeks to process my payment but they did it retroactive to the date they received  it. I knew how backlogged they are so I just waited. 

[br5656]

I posted this question late last night. Lo and behold the check cleared this morning. Thank you all for the replies anyway.