That's probably why your reason was blank. Do a search on here Discover CLI denial then select last 30 days. That's how I found the other post. I know I had to do a HP for CLI. I'm sure that yours was soft they have to ask your permision. That post was from 12/20/2013
Discover IT $17k / US Bank Ace (VSig) $13.5K / US Bank Cash+ (VSig) $13.5k
I've never qualified for a SP CLI from Discover either. If I left it at that, I'd still have my $2000 limit instead of $5000. Sure, I took 2 HP (at 6 months, and at 10 months) but using a HP isn't the big deal that some people make it out to be. they usually don't affect your FICO scores all that much, and after a year they dont affect your FICO scores at all.
@Themanwhocan wrote:I've never qualified for a SP CLI from Discover either. If I left it at that, I'd still have my $2000 limit instead of $5000. Sure, I took 2 HP (at 6 months, and at 10 months) but using a HP isn't the big deal that some people make it out to be. they usually don't affect your FICO scores all that much, and after a year they dont affect your FICO scores at all.
+1 I felt it was worth a HP for the great customer service. I did get mine to $2500 with a SP a year or so ago. My Fico scores are already back to where they were after the HP. I asked for mine about 2 months ago. I also got my Sams card about a month before that.
On the website, just put a number higher than what you want and a credit analyst will call you no later than a few days, asking you why you want the increase and what they will offer short of a HP. I did this going from $6k to $10.5k last week by putting in $18k as my desired increase online.
Now Discover is my highest CL card 
@heyitsyeh wrote:On the website, just put a number higher than what you want and a credit analyst will call you no later than a few days, asking you why you want the increase and what they will offer short of a HP. I did this going from $6k to $10.5k last week by putting in $18k as my desired increase online.
Now Discover is my highest CL card
Not everyone gets the option to request it online though. It asks me to call the 1800 number (without even me entering anything).
Btw, if we request a CLI through HP (over the phone), does Discover counter? I'm afraid of requesting a number that's too high and them rejecting me outright.
Yes, Discover counters. I asked for a HP to $4K over the phone 7 months ago and the rep told me she could only go to $3750. That's my limit now.
The same exact thing happened to me with my Walmart Discover. When I ask for a CLI I was denied and told that I would get a letter within 10 days saying why. I tried calling them and pretty much got a rep that didn't want to discuss it and pretty much told me that it had been denied and they couldn't do anything about it and I would be receiving my 10 day letter. When I received the letter, the reason was blank. I got fed up and just left it be.
I had started with an $800 limit when I was first approved. 3-4 months later THEY increased my limit to $1800 without me asking. It had been another 4 months and that's when I ask and was denied.
So this month I went online and just hit the love button for giggles and they approved me with an instant increase and I'm now at $4300. I have never been late on my bills or with this card and you can see my scores in my sig (which I obtained this year after my last baddie fell off after 7 years).
Give it some more time and try the love button and see if it happens. It worked for me. 
I also did this with another cc that I had been denied for and got an increase with them as well. I swore I would never call and ask for another increase ever again. LOL
@audia4 wrote:The same exact thing happened to me with my Walmart Discover. When I ask for a CLI I was denied and told that I would get a letter within 10 days saying why. I tried calling them and pretty much got a rep that didn't want to discuss it and pretty much told me that it had been denied and they couldn't do anything about it and I would be receiving my 10 day letter. When I received the letter, the reason was blank. I got fed up and just left it be.
I had started with an $800 limit when I was first approved. 3-4 months later THEY increased my limit to $1800 without me asking. It had been another 4 months and that's when I ask and was denied.
So this month I went online and just hit the love button for giggles and they approved me with an instant increase and I'm now at $4300. I have never been late on my bills or with this card and you can see my scores in my sig (which I obtained this year after my last baddie fell off after 7 years).
Give it some more time and try the love button and see if it happens. It worked for me.
Walmart Discover and Discover Financial Services are two totally separate cards/products - different entities. Walmart Discover is issued by GECRB, unlike the Discover it or Discover More cards. They only share the same payment network.