Mailed returns are processed by understaffed, overworked humans at the IRS, and although it should be showing up after about 4 weeks on the IRS site when you mail it, it is likely taking longer. If you used a mailing service that tracked it like UPS or certified mail, and you KNOW the IRS received it, give it a little more time to show up on the WMR site.
**Disclaimer: Every effort has been made to offer the most correct information possible. The poster disclaims any legal responsibility for the accuracy of the information that is contained in this post.**