My taxes were submitted/accepted on 3/31 and I received my state return on 4/21 but not my federal. Wheresmyrefund doesn't tell me anything. What should I do now?

I also received a letter in the mail today (8/8/20) saying my 2018 federal return is being mailed to me but I haven't heard anything about my 2019 and 2017 federal return. I have already received my state taxes for 2017, 2018, 2019. I mailed 2017 and 2018 taxes in mid March and e-filed my 2019 taxes.