The GSLV-F06 flight was unsuccessful following an explosion at around T+60 seconds.
The S139 does have a very good record flying on both the PSLV and the GSLV, so it would come somewhat as a surprise if it did cause the failure. The strap-on boosters would be another suspect having previously failed on one of the GSLV flights.
It would be too early to debate the exact cause until there some official response from ISRO into what caused the failure.
