From the alert box after trying to log in: Connection failed. /usr/lib64/x2go/x2gocheckport: line 131: connect('dbname=/var/lib/x2go/x2go_sessions','',...): syntax error in expression (error token is "('dbname=/var/lib/x2go/x2go_sessions','',...)") /usr/lib64/x2go/x2gocheckport: line 131: connect('dbname=/var/lib/x2go/x2go_sessions','',...): syntax error in expression (error token is "('dbname=/var/lib/x2go/x2go_sessions','',...)") /usr/lib64/x2go/x2gocheckport: line 131: connect('dbname=/var/lib/x2go/x2go_sessions','',...): syntax error in expression (error token is "('dbname=/var/lib/x2go/x2go_sessions','',...)") /usr/lib64/x2go/x2gocheckport: line 131: connect('dbname=/var/lib/x2go/x2go_sessions','',...): syntax error in expression (error token is "('dbname=/var/lib/x2go/x2go_sessions','',...)") /usr/lib64/x2go/x2gocheckport: line 131: connect('dbname=/var/lib/x2go/x2go_sessions','',...): syntax error in expression (error token is "('dbname=/var/lib/x2go/x2go_sessions','',...)") /usr/lib64/x2go/x2gocheckport: line 131: connect('dbname=/var/lib/x2go/x2go_sessions','',...): syntax error in expression (error token is "('dbname=/var/lib/x2go/x2go_sessions','',...)") /usr/lib64/x2go/x2gocheckport: line 131: connect('dbname=/var/lib/x2go/x2go_sessions','',...): syntax error in expression (error token is "('dbname=/var/lib/x2go/x2go_sessions','',...)") /usr/lib64/x2go/x2gocheckport: line 131: connect('dbname=/var/lib/x2go/x2go_sessions','',...): syntax error in expression (error token is "('dbname=/var/lib/x2go/x2go_sessions','',...)") /usr/lib64/x2go/x2gocheckport: line 131: connect('dbname=/var/lib/x2go/x2go_sessions','',...): syntax error in expression (error token is "('dbname=/var/lib/x2go/x2go_sessions','',...)") /usr/lib64/x2go/x2gocheckport: line 131: connect('dbname=/var/lib/x2go/x2go_sessions','',...): syntax error in expression (error token is "('dbname=/var/lib/x2go/x2go_sessions','',...)") Unable to find free display port or insert new session into database;

X2Go was automatically updated a few days ago and stopped allowing users to login on one of our hosts. x2goserver-4.1.0.3-9.fc32.x86_64 5.8.18-200.fc32.x86_64 parameters: port (50), hostname (myhost.edu) and session name ().

from /var/log/messages: Nov 16 09:31:20 ourdomain kernel: audit: type=1105 audit(1605537080.463:18641): pid=1392265 uid=0 auid=1000 ses=401 msg='op=PAM:session_open grantors=pam_selinux,pam_loginuid,pam_selinux,pam_namespace, pam_keyinit,pam_keyinit,pam_limits,pam_systemd,pam_unix,pam_umask,pam_lastlog acct="localguy" exe="/usr/sbin/sshd" hostname=xx.xx.xx.xx addr=xx.xx.xx.xx terminal=ssh res=success' Nov 16 09:31:20 ourdomain kernel: audit: type=2404 audit(1605537080.463:18642): pid=1392275 uid=0 auid=1000 ses=401 msg='op=destroy kind=server fp=SHA256:82:cc:b1:c1:18:02:11:25:68:a7:eb:ec:2a:ed:20:5e :81:1e:66:13:59:f4:7e:ea:ea:06:90:49:81:e8:33:f4 direction=? spid=1392275 suid=0 exe="/usr/sbin/sshd" hostname=? addr=? terminal=? res=success' Nov 16 09:31:23 ourdomain /usr/bin/x2gostartagent[1392479]: no free display number available, cannot start new session. Retrying (run 1). Nov 16 09:31:23 ourdomain /usr/bin/x2gostartagent[1392488]: no free display number available, cannot start new session. Retrying (run 2). Nov 16 09:31:23 ourdomain /usr/bin/x2gostartagent[1392497]: no free display number available, cannot start new session. Retrying (run 3). Nov 16 09:31:23 ourdomain /usr/bin/x2gostartagent[1392506]: no free display number available, cannot start new session. Retrying (run 4). Nov 16 09:31:23 ourdomain /usr/bin/x2gostartagent[1392515]: no free display number available, cannot start new session. Retrying (run 5). Nov 16 09:31:23 ourdomain /usr/bin/x2gostartagent[1392524]: no free display number available, cannot start new session. Retrying (run 6). Nov 16 09:31:24 ourdomain /usr/bin/x2gostartagent[1392533]: no free display number available, cannot start new session. Retrying (run 7). Nov 16 09:31:24 ourdomain /usr/bin/x2gostartagent[1392546]: no free display number available, cannot start new session. Retrying (run 8). Nov 16 09:31:24 ourdomain /usr/bin/x2gostartagent[1392555]: no free display number available, cannot start new session. Retrying (run 9). Nov 16 09:31:24 ourdomain /usr/bin/x2gostartagent[1392564]: no free display number available, cannot start new session. Retrying (run 10). Nov 16 09:31:24 ourdomain /usr/bin/x2gostartagent[1392565]: Unable to find free display port or insert new session into database; parameters: port (50), hostname (ourdomain.edu) and session name ().

Running x2godbadmin --createdb made no difference.

I've seen this mentioned on the list previously in 2018 but no response: https://lists.x2go.org/pipermail/x2go-user/2018-July/005172.html and a CentOS user who did not find a solution at https://centosfaq.org/centos/problems-with-x2go/