If you already mailed your return, you should not efile it after the fact. Right now the delay is due to Covid-19. The IRS has started processing mail again, but had not been and that is why your return does not show it has been received yet. If you efile now, it will likely cause additional delays once they process your mailed return.
There is a delay in processing the returns as the IRS is not processing paper returns at the moment due to Covid-19 and social distancing policies in effect.
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