Unable to join domain

Issue

Unable to join domain to Active Directory server with these error

GSSAPI Error: Unspecified GSS failure. Minor code may provide more information (Server not found in Kerberos database) ...
! Couldn't authenticate to active directory: SASL(-1): generic failure: GSSAPI Error: Unspecified GSS failure. Minor code may provide more information (Server not found in Kerberos database) 
adcli: couldn't connect to [redacted] domain: Couldn't authenticate to active directory: SASL(-1): generic failure:  
! Insufficient permissions to join the domain realm: Couldn't join realm: Insufficient permissions to join the domain ...

Caused

Some UDP port is blocked by firewall

53/udp  open
123/udp open|filtered
88/udp  open|filtered
389/udp open|filtered
464/udp open|filtered
137/udp open|filtered
138/udp open|filtered
636/udp open|filtered

Resolution

Open firewall to UDP port on AD server

53/udp  open
123/udp open
88/udp  open|filtered
389/udp open
464/udp open|filtered
137/udp open|filtered
138/udp open|filtered
636/udp closed

References

• https://stackoverflow.com/questions/75795309/oel8-realm-join-error-insufficient-permissions-to-join-domain
• https://serverfault.com/a/1155757/200746