I have a dataset of 5 years panel data of more than 30,000 cities. However, when I run regression ppml, zero-inflated poisson.
my code:

*logit model
logit $ylist $x1list

vce, corr

logit $ylist $x2list

*zero-inflated poisson
drop if $ylist==0

xtpoisson $ylist $x3list, iterate(5)
*detect collinearity
No matter how much I put it in the iterate bracket, the iteration still goes up to 5000 and keep running. I halted because I understand MLE model aint suppose to have so many iterations.

Would any expert here know what is the problem here? How can I solve it? how many iteration may I set?