Nomachine: The server was unable to make the local display available or access to the local display is disabled

After my server has run out of RAM, unstable nomachine remote desktop tool has disconnected and now, after reboot of the server, it doesn't want to connect saying:

The server was unable to make the local display available or access to the local display is disabled.

I tried reinstalling server-side nomachine's DEB file with purging. Tried reinstalling MATE desktop, I still get this message and I don't know what to do. How to make it work again?

Tried to run /usr/NX/bin/nxserver --restart it also doesn't help.

Also tried restarting nxserver service, I've found some strange errors in journalctl:

Feb 17 01:42:44 37-61-214-198 nxexec[3532]: (mount.c:72): Messages from underlying mount program:
Feb 17 01:42:44 37-61-214-198 nxexec[3532]: (mount.c:76): mount error: could not resolve address for SERVEUR: Unknown error
Feb 17 01:42:44 37-61-214-198 nxexec[3532]: (pam_mount.c:522): mount of public failed
Feb 17 01:42:44 37-61-214-198 nxexec[3532]: (mount.c:72): Messages from underlying mount program:
Feb 17 01:42:44 37-61-214-198 nxexec[3532]: (mount.c:76): mount error: could not resolve address for SERVEUR: Unknown error
Feb 17 01:42:44 37-61-214-198 nxexec[3532]: (pam_mount.c:522): mount of commun failed
Feb 17 01:42:54 37-61-214-198 nxexec[6004]: pam_unix(nx:session): session opened for user gdm by (uid=129)
Feb 17 01:43:11 37-61-214-198 systemd[1]: nxserver.service: Succeeded.
Feb 17 01:43:11 37-61-214-198 systemd[1]: Stopped NoMachine Server daemon.
Feb 17 01:43:12 37-61-214-198 systemd[1]: Started NoMachine Server daemon.
Feb 17 01:43:13 37-61-214-198 nxexec[6212]: pam_unix(nx:session): session opened for user gdm by (uid=129)
Feb 17 01:44:16 37-61-214-198 nxexec[6633]: pam_ldap(nx:account): error reading from nslcd: Connection reset by peer
Feb 17 01:46:59 37-61-214-198 systemd[1]: Stopping NoMachine Server daemon...
Feb 17 01:46:59 37-61-214-198 nxexec[6212]: (mount.c:72): Messages from underlying mount program:
Feb 17 01:46:59 37-61-214-198 nxexec[6212]: (mount.c:76): mount error: could not resolve address for SERVEUR: Unknown error
Feb 17 01:46:59 37-61-214-198 nxexec[6212]: (pam_mount.c:522): mount of gdm failed
Feb 17 01:46:59 37-61-214-198 nxexec[6212]: (mount.c:72): Messages from underlying mount program:
Feb 17 01:46:59 37-61-214-198 nxexec[6212]: (mount.c:76): mount error: could not resolve address for SERVEUR: Unknown error
Feb 17 01:46:59 37-61-214-198 nxexec[6212]: (pam_mount.c:522): mount of public failed
Feb 17 01:46:59 37-61-214-198 nxexec[6212]: (mount.c:72): Messages from underlying mount program:
Feb 17 01:46:59 37-61-214-198 nxexec[6212]: (mount.c:76): mount error: could not resolve address for SERVEUR: Unknown error
Feb 17 01:46:59 37-61-214-198 nxexec[6212]: (pam_mount.c:522): mount of commun failed
Feb 17 01:47:09 37-61-214-198 nxexec[7379]: pam_unix(nx:session): session opened for user gdm by (uid=129)
Feb 17 01:47:11 37-61-214-198 nxexec[7379]: (mount.c:72): Messages from underlying mount program:
Feb 17 01:47:11 37-61-214-198 nxexec[7379]: (mount.c:76): mount error: could not resolve address for SERVEUR: Unknown error
Feb 17 01:47:11 37-61-214-198 systemd[1]: nxserver.service: Succeeded.
Feb 17 01:47:11 37-61-214-198 systemd[1]: Stopped NoMachine Server daemon.
Feb 17 01:47:11 37-61-214-198 nxexec[7379]: (pam_mount.c:522): mount of gdm failed
Feb 17 01:47:11 37-61-214-198 nxexec[7379]: (mount.c:72): Messages from underlying mount program:
Feb 17 01:47:11 37-61-214-198 nxexec[7379]: (mount.c:76): mount error: could not resolve address for SERVEUR: Unknown error
Feb 17 01:47:11 37-61-214-198 nxexec[7379]: (pam_mount.c:522): mount of public failed
Feb 17 01:47:11 37-61-214-198 nxexec[7379]: (mount.c:72): Messages from underlying mount program:
Feb 17 01:47:11 37-61-214-198 nxexec[7379]: (mount.c:76): mount error: could not resolve address for SERVEUR: Unknown error
Feb 17 01:47:11 37-61-214-198 nxexec[7379]: (pam_mount.c:522): mount of commun failed
Feb 17 01:47:12 37-61-214-198 systemd[1]: Started NoMachine Server daemon.
Feb 17 01:47:12 37-61-214-198 nxexec[7552]: pam_unix(nx:session): session opened for user gdm by (uid=129)
Feb 17 01:47:26 37-61-214-198 nxexec[7632]: pam_ldap(nx:account): error reading from nslcd: Connection reset by peer
Feb 17 01:49:19 37-61-214-198 systemd[1]: Stopping NoMachine Server daemon...
Feb 17 01:49:19 37-61-214-198 nxexec[7552]: (mount.c:72): Messages from underlying mount program:
Feb 17 01:49:19 37-61-214-198 nxexec[7552]: (mount.c:76): mount error: could not resolve address for SERVEUR: Unknown error
Feb 17 01:49:19 37-61-214-198 nxexec[7552]: (pam_mount.c:522): mount of gdm failed
Feb 17 01:49:19 37-61-214-198 nxexec[7552]: (mount.c:72): Messages from underlying mount program:
Feb 17 01:49:19 37-61-214-198 nxexec[7552]: (mount.c:76): mount error: could not resolve address for SERVEUR: Unknown error
Feb 17 01:49:19 37-61-214-198 nxexec[7552]: (pam_mount.c:522): mount of public failed
Feb 17 01:49:19 37-61-214-198 nxexec[7552]: (mount.c:72): Messages from underlying mount program:
Feb 17 01:49:19 37-61-214-198 nxexec[7552]: (mount.c:76): mount error: could not resolve address for SERVEUR: Unknown error
Feb 17 01:49:19 37-61-214-198 nxexec[7552]: (pam_mount.c:522): mount of commun failed
Feb 17 01:49:29 37-61-214-198 nxexec[8168]: pam_unix(nx:session): session opened for user gdm by (uid=129)
Feb 17 01:49:46 37-61-214-198 systemd[1]: nxserver.service: Succeeded.
Feb 17 01:49:46 37-61-214-198 systemd[1]: Stopped NoMachine Server daemon.
Feb 17 01:49:46 37-61-214-198 systemd[1]: Started NoMachine Server daemon.
Feb 17 01:49:47 37-61-214-198 nxexec[8347]: pam_unix(nx:session): session opened for user gdm by (uid=129)
Feb 17 01:50:03 37-61-214-198 nxexec[8445]: pam_ldap(nx:account): error reading from nslcd: Connection reset by peer