I’m not sure if you understands Mbps correctly since Mbps and MB/s (uppercase and lowercase B) are two different things.
Since you mentioned browser download I’m going to assume MB/s.
Free hosting doesn’t allow any files over 10 MB in size.
7 * 1.4 = 9.8 which is very close to 10, so that might explain why everything that takes more than 7s will fail.