Asking for help about the IPFS api using

Questions
1

When I use the api
curl ipfs.infura.io: 5001/ api/ v0/ add? pin=false
-X POST
-H Content-Type: multipart/form-data
-F file=@[file name]

to push a file to ipfs network.
Why don’t i get the file by using url like “gateway. ipfs. io / ipfs/ [The hash of a file]” But can get the file by using url “ipfs.infura.io: 5001/ api/ v0/cat? arg=[The hash of a file]” ?

[UPDATE]
Actually, I can get the file by using gateway. ipfs. io / ipfs/ domain now. It is time delay ? It has serveral minutes gap…

2

Have you experienced this on many adds? How large is the file?

3