Two military satellites planned to be launched before end of 2017 are delayed due the technical problems. The fourth Advanced Extremely High Frequency protected communications spacecraft and fourth Space Based Infrared Systems-Geosynchronous missile tracking satellites will reach orbit in first months of 2018.
Satellites were planned to be launched on October 11, 2017 and November 9 2017 respectively. SBIRS-GEO-4 was moved to 2018 because of program prioritization decision (as claims USAF) and AEFH-4 has technical problems spotted in factory - USAF officially confirmed that both satellites dropped from 2017 launch schedule.
AEFH-4 satellite manufactured by Lockheed Martin and Northrop Grumman with utilization of A2100M bus by Lockheed Martin. Technical problems are referring to power regulator unit, still USAF and Lockheed Martin are not officially declaring what exactly was the problem and how long it will take to solve it. Probably regulator unit will be modified but it seems that it is not huge deal for Lockheed Martin as USAF already announced, that AEFH-4 probably will be launched on the top of the Atlas v (531 configuration) on January 18th, 2018 from SLC-41 at Cape Canaveral. SBIRS-Geo-4 probably will reach orbit also in January 2018 on the top of the Atlas V (411 configuration). SBIRS will be launched also from SLC-41 at Cape Canaveral.