I submitted my Tax Return on 1/15/19, and the day after, the WMR tool showed “Return Received: We have received your Tax Return and it is being processed.” BUT THEN..?

I submitted my Tax Return on 1/15, and the day after, the WMR tool provided by the IRS showed “Return Received: We have received your Tax Return and it is being processed.” And then 3 days later, it has started showing me “We cannot provide you any information about your refund, if you filed a complete and accurate return, you should receive your refund in about 21 days...”