IP requires whitelisting

[audiopro]

I have a dynamic IP address and whenever it changes, it needs to be whitelisted before I can transfer files.
I understand that but wonder why, when an IP is effectively blocked, can the server still be accessed.

According to the log, the connection is established and it only fails on the final dir retrieval.

Is this expected behaviour or is there something wrong here?

Status: Connecting to xx.xxx.xxx.xxx:21...
Status: Connection established, waiting for welcome message...
Status: Initializing TLS...
Status: Verifying certificate...
Status: TLS connection established.
Status: Logged in
Status: Retrieving directory listing of "/public_html/xxxxx"...
Command: CWD /public_html/xxxxx
Response: 250 OK. Current directory is /public_html/xxxxx
Command: PWD
Response: 257 "/public_html/xxxxx" is your current location
Command: TYPE I
Response: 200 TYPE is now 8-bit binary
Command: PASV
Response: 227 Entering Passive Mode (xx,xxx,xxx,xxx,xxx)
Command: MLSD
Error: Connection timed out after 20 seconds of inactivity
Error: Failed to retrieve directory listing
Status: Disconnected from server

[botg]

FTP uses multiple connections: A control connection to issue commands and receive replies, and individual data connections for each individual transfer.

Looks like there is no IP filtering on the control connection port.