received IRS notice CP162A, "Failure to file penalty"

I started 2 LLC's in 2020 (partnership), and filed Form 1065 for both in 3/2021 and 3/2022, by "turbotax business". I have screen shots supporting successful submission and acceptance of both tax-filling in both years. 

 

then received notice CP162A with tax period "4/30/2021", stating "8months late", asking for penalty of $210 per partner per month.

then another CP162A for the other LLC for tax period "11/30/2021". stating "1month late". asking for penalty of same $210 per partner per month. 

I have no idea what I was late for, and why the second notice has a different tax period and "1 month late". 

I tried to call IRS, everyday for the past 4 weeks, I always got "I am sorry Due to extremely high call volumes, we are not able to handle your call today. please try again another day". 

the IRS website is not very helpful on what I was late for. 

any of you have similar issues? 

thank you for the attention.