I have no problem getting response or their interest. But there is a trend, after couple emails exchange ( usually 3-4 ), I usually end up with 2 scenarios:
1. I asked for phone number and they flake. ( I was given advices that I didn't build enough comfort )
2. I don't ask for number as I want to build more comfort and attraction. The connection dies out and they flake on responding.
They could have some issues on their owns or something else, but I don't think the failure lies entirely on my part. But I would like some input on this.
Here is an example of one of my encounter.
I have this girl who is totally into me, showing excessive amount of IOIs, emails were full of "!!!" and smileys. When I asked for her number, she tried to break tension by throwing me a loop, I reframed and replied with
"I forgot you dont know how to use cellphone, too bad texting is way too much fun to pass. But don't worry, I'll send you smoke signal when the time comes, hope you know morse code"
She replied with "Oh you're think you're so funny !!! ( and DAMN you're are

)"
I didn't want to appear desperate for her numberr so I didn't reply after this, now seem like she lost interest.