opto isolated igbt driver

i am constructing an igbt driver using this part https://www.electro-tech-online.com/custompdfs/2008/01/86257.pdf
in the schematic, it uses an opto isolator. i have got the basic circuit to work (by grounding the in pin grounds the output voltage). i have also got an opto isolator to work (by passing a 10khz signal through it), but when i integrate the 2 systems nothing works... sigh! any ideas?

The input should be below 0.8 volts for a low. The opto may not be able to pull the input that low.

The pullup resistor should pull up to 4.2 volts with a 1uA load.

So the question is; what is the high and low voltage on the input.

Do not pull more than 10mA from the reference voltage.