After upgrade FTP doest work anymore

Question

We upgrade CompleteFTPSetup-21.0.0 to CompleteFTPSetup-21.1.0.
And reboot the server.

Seems that FTP is not working. Even disabled FTP and enabled. 

LOG:
Connected to SERVER (**IP_MASKED_INTERNAL**).
220-Complete FTP server
220 CompleteFTP v 21.1.0
421 Service not available, remote server has closed connection
Not connected.
Local directory now /bla/bla2
Not connected.

After desinstalling and downgradeing it works again.
No Entrys in server log.

SSH FTP worked all the time

Comments

We will need a debug log for this, so we would kindly ask you to open up a support ticket here and attach a log set at debug level showing the issue. 

---

We don't have a debug log for now.
As we downgraded the server to get it working again getting a debug log this might take a while.
We will try to setup a test enviroment for it.

---

Ok. If you get the Debug log please use the link shown above as you have a current support agreement in place.

---

One thing to check is the firewall - make sure it is allowing connections. You can test a release as described here
https://enterprisedt.com/questions/index.php/11604/how-can-i-test-that-a-new-release-works-for-my-server