Linux ncftput upload is slow.

You are about to upload to FTP from the CDN service on the Linux server.
But the upload speed went up to tens of megabytes per second when it first ranGo
In terms of capacity, it's all uploaded, but the upload speed is still
It drops down to a few bytes per second and does not complete the upload or move on to the next file.

If you look at it, it's actually on the CDN, but on the Linux server, it looks like you're uploading a file by a few bytes, and it doesn't stop. I can't predict what's wrong with these symptoms, so if anyone knows, please answer.

Thank you.