The best way to answer this question is to look at your landing page.

However, I will try to list few things that MIGHT cause this:

1. NO VALUE:
The user may perceive that there is nothing much gained in subscribing to your emails.

2. NOT ENOUGH TRAFFIC:
You may not be getting enough traffic to get email subscribers. Point is, not 100% of the traffic subscribes to email. It may be, say 5%. Now, if are getting just 20-30 users, it may not be enough to get enough subscribers.

3. WRONG LOCATION:
The place where you are asking for emails, may not the right location.

4. WRONG AUDIENCE:
It may also happen, that you might be targetting/attracting the wrong audience in the first place, who don't want to share their emails.

Best thing to do would be to give something in exchange of emails, like free e-book, whitepaper, etc. which would be useful to the user. Also, create multiple landing pages and do A/B testing.

This will increase your chances of getting more emails.

Hope this helps.

If you do not want any downloads from specific countries, why not exclude these countries for your app sale. Then you don't have to worry about span downloads, etc.

I am the owner of a Mobile Apps development Company. We have developed more than 200 apps till now for our clients. While working and seeing our clients make money with apps, this is what I can summarize for making money for free B2C apps:

Before that, I assume that your app fulfils the following criteria:
1. Satisfies a need. Need can be any task which can be done on the go.
2. App has UI which is simple to understand and does not require you to provide "image overlays" to explain what the app does.

There are two steps to make money:
1. Get more downloads
2. Then make a pitch.

1. Get more downloads:
* Don't plan to put all features in single update. Split it into multiple updates and update the app regularly, make be once a week. This way your app will keep coming in latest apps section on the appstore. I am sure you would have noticed an uptick in downloads in days following the release of your app.

2. Make a pitch
* Find out the general profile of your users. Knowing this you will have fair idea about their needs. Now, find providers who can fulfil their needs.

If nothing works, put your app as paid app at a higher price, say $4.99 or $6.99. I have seen people make good money using this strategy too.

Without knowing what your app is, that is all I can say.

If you have any questions, please feel free to call or email me.

Good luck!

Priyadarshan Joshi
CEO
TaxSmart Technologies Pvt. Ltd
pjoshi@itaxsmart.com