Getting a mortgage with 30k W2 income

[Alex Silang]

This is my financial situation:

30k income

Rental property (I own):

4k monthly rent
1.5k/mo PITI

Want to buy:

350k-400k property
4k monthly rent

I've used online calculators (for what they're worth) and they say I qualify. Also, another mortgage broker showed me how to calculate DTI ratio and I pass.

However, I emailed a mortgage broker recently and he said "not a sure thing". Is he just trying to cover himself, or am I at high risk of getting rejected? Is there something as I'm missing?