Follow up with a written rejection of their application citing the reasons for the rejection.

I also keep the records of investors who are not qualified, so I can demonstrate that I am rejecting unqualified people.As far as getting investors is concerned, this is a process.  

I even made offers on two of them, one was rejected.

And the coop board process can take months, with lots of nonrefundable fees, just to be rejected with no reason given.Back in the 70's and 80's many of the corporations ran into financial trouble because the share holders stopped paying their mortgages so the corporations had to raise their maintenance fees to cover the interest payments.

What I did wrong are (don't repeat my mistakes >O<):1) I had offers rejected instantly or ignored the day before, I felt upset and got carried away2) I listened to the agent way too much without doing lots research myself, the agent said the house will go up 8000k more on the asking price and will have many offers and I listened >O<.3) I really didn't think I'll get accepted that quickly LOLThe asking price is 125k, my offer is 130k, zestimate is about 128k but i know it's debatable... 

I think a lot of people go to these classes thinking it will be the answer to their problems when the problem is inaction, insecurity, and fears of failure, poverty, and rejection.

The appraiser rejected my banks request to remove “fix before closing” clause in the report.

If you reject someone for not having 3x income, but accept another renter with only 2.5x you could be opening yourself us to a FHA lawsuit. 

Now, if you've gone down that road and have 10 rejections under your below you may have to adjust expectations, geography, etc.

Show comps (recent sales wherever possible), and repair estimates following a walk-through, and explain that these are factors to be taken into account by an investor when purchasing.Finally, remember:- You make your money when buying, not when you sell - we send out 20 -30 offers every day, most get rejected, but that doesn't stop us making similar offers (based on our calculations) the very next day.Good luck.