Unable to upload files to server (FileZilla -> Ubuntu, VSFTPD). What is the reason?

Question

ubuntu

Before there were no problems, everything was loaded normally.
Today I uploaded about 10-15Gb of information to the server via ftp, everything loaded fine, but at some point filezilla began to refuse to upload:
Failed transfers .... Reason: "Transfer" <-what could this mean
. At the same time, no errors in the logs no
Files are deleted without problems, directories are created. But files are not transferred.
I connect under another user, everything is fine, the files run back and forth, but not under the right one.
Maybe some volume limits? Moreover, this restriction is similar to a day (an hour or more), since I delete files of 1GB in size, and new smaller ones do not enter. For the first time, can anyone tell me, maybe incorrect settings for VSFTPD or the user?