Yes same issue. IDFC logo loading each time. In my case, my first application attempt had gone thru, but failed later because of connectivity issue. Since then all of next attempts, results in page getting stuck. I guess because of first incomplete application.
I have raised complaint with IDFC. Waiting for resolution.
When I contacted support they asked me what's the limit and they said it will be unlikely to get it upgraded if CL is less than 4L however she opened ticket with name "Card Product Upgrade - Without Limit Enhancement" and it worked.