Comment by VirusNewbie

Did you do practice interviews? I highly recommend doing pramp.com and/or paying for actual interview feedback.

Until you have someone with nothing to lose giving you brutally honest feedback, you won't know what the issue is. Years ago I had thought I passed technical interviews but I had given non optimal code.

I had one mock interviewer (paid) tell me I wasn't explaining my solutions enough and I needed to take charge of the conversation more.

Invest some time into finding out what your real weaknesses are.