Open port 21 for vsftpd at azure

Question

Can't open port 21 on linux Ubuntu 18 at azure. I've configured vsftpd

listen_port=21
pasv_enable=Yes
pasv_addr_resolve=YES
pasv_min_port=5001
pasv_max_port=5050
pasv_address=xx.xx.xx.xx

I've configured NSG at azure, opened inbound port 21 and 5001-5050 ports inbound/outbound, configured ubuntu firewall:

# sudo ufw status verbose
Status: active
Logging: on (low)
Default: deny (incoming), allow (outgoing), disabled (routed)
New profiles: skip

To                         Action      From
--                         ------      ----
9911/tcp                   ALLOW IN    Anywhere
21/tcp                     ALLOW IN    Anywhere
5001/tcp                   ALLOW IN    Anywhere
5002/tcp                   ALLOW IN    Anywhere
5003/tcp                   ALLOW IN    Anywhere
5004/tcp                   ALLOW IN    Anywhere
5005/tcp                   ALLOW IN    Anywhere

telnet localhost 21 working ok, but did not working telnet on external ip. What else I can try ?

Second issue, I can't setup NSG flow logs. The logs requiring storage account, I've created StorageV2 (general purpose v2) account, but can't choose storage account at NSG flow logs dialog.

Update1: I've disabled VM firewall by command: sudo ufw disable

Checked port 21 inside the VM:

root@spark:~# lsof -i -P -n
COMMAND    PID            USER   FD   TYPE DEVICE SIZE/OFF NODE NAME
...
vsftpd    1334            root    3u  IPv4  21219      0t0  TCP *:21 (LISTEN)

No success.

Update2: Just deleted the Ubuntu VM, created VM with centos and it's working.