Problems with Fregat-M were caused probably by navigational and guidance system but not necessary by their technical malfunction.
According to TASS news agency problems with Fregat-M launched from Vostochny Cosmodrome on November 28 were directly linked with guidance system. TASS refers here to anonymous source inside Russian space industry - Agency claims that guidance system, which is basing on GLONASS and GPS signals allowing it to operate with greater precision probably failed in the early phase of flight after separation with third stage. Position of the upper stage after separation is determined by the guidance system, and as it was announced earlier, Fregat-M was not correctly oriented with payload faced to Earth. Still it does not have to be synonymous with technical malfunction of the system.
Problems could be caused by error in program code of guidance computer or (according to RussianSpaceWeb.com) lack of appropriate fragment of code setting launch place to Vostochny Cosmodrome instead Baikonur. Without this fragment of code computer could interpret data from GLONASS and GPS as confirmation of not planned course change. It could cause that guidance system decided to rotate Fregat-M to use first burn for placing it into correct position on designated orbit. Of course in this case it simply caused turning Fregat-M for 180° and starting reentry after first few seconds of burn.
In case of error in code, computer could simply perform wrong maneuver before planned for 77 s first burn. This also would have identical result, in both cases potential reasons will be explained by State Commission which already begun investigation.
According to Roscosmos Fregat-M fall into Atlantic Ocean after reentry. It crushed probably at 42° N and 38 ° W; this sounds very possible as flight attendant at one of British Airways flights over Atlantic recorded video with burning object flying into the ground close to location announced by Roscosmos. In this way second launch from Launch Site 1S at Vostochny Cosmodrome became a failure only 30 minutes after start.