Knowledge Base

Unable to install Plesk license: cURL cannot communicate with license server

License installation on a Plesk server fails:

cURL cannot communicate with license server https://id-00.kaid.plesk.com:443/ (): Couldn't connect to server(7) cURL cannot communicate with license server https://id-00.kaid.plesk.com:443/ (): Couldn't resolve host name(6) (Error code: 2)
The hostname id-00.kaid.plesk.com is correctly resolved over DNS while checking with commands:
- For Linux:
  
  # host id-00.kaid.plesk.com
  id-00.kaid.plesk.com is an alias for ka.plesk.com.
  ka.plesk.com has address 195.214.233.82
  ka.plesk.com has address 195.214.233.80
  ka.plesk.com has address 195.214.233.81
- For Windows:
  
  C:> nslookup id-00.kaid.plesk.com
  Server: UnKnown
  Address: 2620:0:28a9:4::1
  Non-authoritative answer:
  Name: ka.plesk.com
  Addresses: 195.214.233.81
  195.214.233.80
  195.214.233.82
  Aliases: id-00.kaid.plesk.com
The connection to licensing servers fails:
# telnet ka.plesk.com 443
Trying 195.214.233.82...
telnet: Unable to connect to remote host: Connection refused
There are no blocking firewall rules for outbound traffic either in the local Firewall or in the external Firewall (if there is any)
Other operations on the server related to outgoing traffic, for example, packages installation or extensions catalog opening, fail as well:
- For Linux
  
  # apt install nmap -y
  ..........
  Err:1 http://archive.ubuntu.com/ubuntu xenial InRelease
  Could not connect to archive.ubuntu.com:80 (203.0.113.2), - connection timed out [IP: 203.0.113.2 80]
  ..........
  
  # wget https://ext.plesk.com
  --2024-07-09 22:43:42-- https://ext.plesk.com/
  Resolving ext.plesk.com (ext.plesk.com)... 79.127.235.11, 79.127.235.9, 79.127.213.245, ...
  Connecting to ext.plesk.com (ext.plesk.com)|79.127.235.11|:443... connected.
  WARNING: Could not save SSL session data for socket 3
  Failed writing HTTP request: The specified session has been invalidated for some reason..
  Retrying.
  ..........
- For Windows:
  C:> curl https://ext.plesk.com
  curl: (28) Failed to connect to ext.plesk.com port 443 after 21048 ms: Couldn't connect to server