Form 1040X is used to file an amended return. You use it when you have filed a regular return, form 1040, but there is something reported wrong so you file a 1040X to correct it.
If you filed a form 1040X without having first filed a form 1040, then it may not be processed.
If that is what you did, I would suggest you file a form 1040.
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1040-X was suggested way back when the IRS Portal was causing confusion last year.
if you did not get an EIP1 or EIP2 and you are qualified,
file 2020 Form 1040 with the amount you did not get on line 30.
That is the only way.