How long should I wait before my next credit card application, if my first application failed?

I tried applying for the Standard Chartered unlimited cash back, and was promptly rejected. Checked and saw a score of GX. It seems to be a system rejection. I am self employed and I hit the requirement by a decent amount for this year, but falling short of a few thousands for last year's. Also, I used the Singpass Myinfo to apply, does that affect as well?