Filezilla FTP Connection Error

Hello,

Someone is trying to connect to our FTP server however is getting an error message when trying to connect using Filezilla. I have tried myself from an external computer outside out network and it works fine. By looking at the error log, does anyone know what the issue is here?

Thanks in advance.

Status:                      Resolving address of (FTP SERVER)
Status:                      Connecting to (IP ADDRESS):21...
Status:                      Connection established, waiting for welcome message...
Response:               220 Preview Services File Transfer Server
Command:               USER (USERNAME)
Response:               331 Password required for (USERNAME).
Command:               PASS *******
Response:               230 Login OK. Proceed.
Command:               SYST
Response:               215 UNIX Type: L8
Command:               FEAT
Response:               211-Features supported:
Response:               COMB target;source_list
Response:               REST STREAM
Response:               SIZE
Response:               MDTM
Response:               XCRC filename;start;end
Response:               SSCN
Response:               MLST Size*;Modify*;Create;Type*;Unique;Perm*;Lang;Media-Type;CharSet;
Response:               MODE Z 
Response:               XNOP 
Response:               211 END
Status:                      Connected
Status:                      Retrieving directory listing...
Command:               PWD
Response:               257 "/Usr/(FOLDER)" is current folder.
Command:               TYPE I
Response:               200 Type set to I.
Command:               PASV
Error:                        Disconnected from server: ECONNABORTED - Connection aborted
Error:      Failed to retrieve directory listing

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