Started Getting Valid Arc Lost Error

Great news. But it still comes back to trying to do something that is really on the edge of whats reasonable. You should stick to 30 amps and maybe slow the feed rate back to 1500. Assuming you are holding the pipe in a 4th rotary axis there is no need for a THC as the height can't vary. But if you are cutting the pipe sitting on the table, the arc may be lost as the height is changing. YOu need to do it in a rotary axis.

I dont have yet a rotary axes, but i was thinking the thc works when the arc move up or down. I make only a straight row of holes and the difference between upper part was max 1mm. I lose the arc at the end of the cut, maybe when the hole material drop. You are wright, at 30 amp the arc lost was rarely.

1 mm change in height represents a 10 volt change in arc voltage.
Your cut height is 1.5mm by the manual
The torch is not perpendicular to the surface
The voltage peak on piercing has probably not fallen back to cut height by the time your cut is over
There are many things against you. Best solution is to spot the holes and drill.

started new post