Why can i not e-file

It would be hard to know without any info.   What happens when you try?  Do you get any message?

What do you see when you step through the REVIEW section?   Do you get any clue there?

Are you wanting to efile both Federal and state returns?

Tell us the rejection message and maybe we can help.  certain issues are unfixable and require you to mail it in.  they include another return filed before yours which had one or more SSN's on it that match one or more SSN's on yours (this would include filing a return for stimulus payment).  another non fixable issue is sometimes the 2018 adjusted gross income.  Even when correct there is sometimes an issue that prevents e-filing.