Trust me on this: you're not alone! 
Just recently, I posted a thread asking for tips on how to get Discover to [finally] approve a CLI. I kid you not, but three days later I pushed the love button on Discover's site, and got a nice CLI! Maybe you'll have the same luck. 
If that method doesn't work out, I'd suggest making more use of your card. It looks like you're just barely using it, and they like to see considerable activity. Among the denial reasons I had along the way was one saying 'insufficient use of available credit' (or similar). In other words, I wasn't using what was already available to me, so why give me an increase?! I ramped up my spending for several months, but continued getting denied; I figured it was because I still kept my utilization rate too low. And then, out of the blue, I got approved. 
So I suggest having larger, more frequent transactions on your card, wait until the moon is full, stand on your head, make sure there's a 'd' in the day's name, and press the magic button!
@Anonymous wrote:
@Sbrooks1 wrote:I can't get approved for a CLI on Discover for years, Same limit I had when I opened it, 6500, I have 2 % UTI and never carry a balance on this card, only use for Netflix monthly, is that why? Should I just get rid of it? My other cards have 15-30 limits.
When you apply for a CLI with Discover and it is denied they will send to you by regular postal mail a letter with the reason why you where denied. Once you receive that please post the issue so we can see if we can figure out the best cause of action.
Thanks
Mark
Im guessing insufficient experience at current limit or low usage as they are most common. Best way to remedy that is to actually use the card
@Anonymous wrote:If it's an old account it might be a bad idea to close it, if it would impact your AAoA because that impacts your Fico
also, you'd be losing $6,5k of credit from your Total Revolving Credit which might impact your score if you have any debt on other cards... tho you say 2% uti so maybe not.
Not sure if you've tried to CLI via the chat function In the app or on line. Often those folks can get you what you want. Good luck!
Closing an account does not affect ones AAoA, still factors in
@Michizane wrote:You need to put a lot of spend on their cards and pay it off before the statement cuts. I got 2 CLI's (500>1000>2000) after I significantly put more spend on the card. I've had the $500 CL for like 6 years before I got the first CLI this year.
I would try putting a couple hundred of spend on it, and try for a CLI a few days after your statement cuts. Discover is running 5% back on restaurants and PayPal ($1500/$75 cashback for the quarter) till next month which is awesome (Anytime you use PayPal as payment). Especially since since quite a few sites take PayPal as payment. I've been able to rack up a ton of spend buying stuff online for in store pickup for Home Depot, Best Buy, etc.
Discover is so over the place with who and how they give a cli, ones method doesnt necessarily work for other. Paying off before a statement cuts doesnt equate to getting a cli, it just appears thats how it worked out for you. I think the only thing we may be certain of with Discover is using the card is a much more viable option than not