Hi, I am experiencing a weird problem of my car not starting on HOT DAYS ONLY.

Car: 2007 Toyota Corolla, 120k miles, 1ZZ-FE engine

Facts:

1. Car has no problem starting unless the outside temperature is 95F+
2. If it's a hot day and the car has been sitting in the sun, then there's about 20% chance the car won't start
3. When the car doesn't start I can hear the engine cranking no problem
4. I can see a recurring DTC code: B2799 Immobilizer malfunction
5. This problem does not depend on engine temperature

I've tried the following:

1. Replaced fuel pump relay (C/OPN relay)
2. Replaced fuel injector relay (EFI relay)
3. I ran an Oxygen sensor #2 test using Techstream and it seems to work just fine
4. Cleaned MAF sensor
5. Battery is good
6. Air filter is good

I will be happy for any input!