What year are you filing? 2020 is not over yet and the IRS has not finalized all the forms yet. Efiling won't open until late January. And you have not received all your W2s and 1099 forms yet. And there will be many program updates to come. Please be patient and wait to get your forms from your employers.
Please be careful about being in too much of a hurry to file your next tax return. Many tax forms are not available at the very beginning of the tax season, so you have to wait for your forms. The software still needs updates at the beginning of the tax season.
Although the software will allow you to e-file in early January, the IRS does not begin to accept the e-files until almost the end of the month. So your return just sits on the server. If you realize that you made a mistake or left something out—as many people do—you cannot change it.
Every year we see people who are in such a rush to file that they file incorrectly and incompletely. If you file too early and leave out a W-2 or a 1099, or forget to enter information, you will end up having to amend your tax return---and that takes months. Employers have until the end of January to issue W-2's----and ALL of your 2020 W-2's have to be on the same tax return. Many of the 1099's and 1098's you need do not arrive until late January or sometime in February. If you are getting Earned Income Credit or Additional Child Tax Credit, the IRS is going to hold your refund until the end of February no matter how early you file. There seems to be a greater chance of "early" returns being reviewed and those refunds are delayed, or early returns are more often subject to identity verification--which will also delay processing. Filing too early may just be a recipe for a delayed refund. It might go more smoothly for you if you wait until at least mid-February to file instead of e-filing during the first minute that you can do it.
If....if...you are asking why you cannot file your 2019 return--it is because the deadline to e-file was in October and now e-filing is closed for 2019 returns. If you need to file a 2019 return then the only way to file it is to print, sign and mail it now. We can give you more information if that is what you need to do.