The taxpayer advocate posted a blog last Thursday announcing the IRS has a return processing backlog of more than 29-million tax returns at this point.

Causes include inability to reprogram IRS computers for late tax law changes Congress passed in December and March, as well as resource overload from additional activities loaded onto the IRS by Congress.

https://www.taxpayeradvocate.irs.gov/news/nta-blog-2021-filing-season-bumps-in-the-road-part-1/