E-file, e-services Unavailable over Labor Day Weekend
Several IRS systems will be unavailable over the Labor Day weekend due to scheduled power outages:

E-services and Modernized e-File will be unavailable from Sunday, Sept. 6 at 9 p.m. ET until Tuesday, Sept. 8 at 5 a.m. ET.
Electronic Management System (EMS) in Memphis, Tenn., will be unavailable from Saturday, Sept. 5 at 9 p.m. ET until Monday, Sept. 7 at 7 a.m. ET.
EMS in Martinsburg, W.Va., will be unavailable from Sunday, Sept. 6, at 2 p.m. ET until Tuesday, Sept. 8 at 6 a.m. ET.
E-file transmissions will not be accepted during these times
This is the only time during the year that we are aware that this happens.
this report directly comes from the irs.gov site