Eos 5.5.0 breakage : MGM root://localhost not online/reachable

so, after updating all my mgms to 5.5.0 trying an eos fs ls
gives error: MGM root://localhost not online/reachable
but the service seems running:
systemctl status eos@mgm
eos@mgm.service - EOS mgm
Loaded: loaded (/etc/systemd/system/eos@.service;enabled; preset: disabled)
Active:active (running)since Mon 2026-07-06 11:19:58 EEST; 28min ago
Main PID: 1007 (xrootd)
Tasks: 594 (limit: 822564)
Memory: 5.5G (peak: 5.5G)
CPU: 2min 56.120s
CGroup: /system.slice/system-eos.slice/eos@mgm.service
├─1007 /opt/eos/xrootd/bin/xrootd -n mgm -c /etc/xrd.cf.mgm -l /var/log/eos/xrdlog.mgm -Rdaemon
├─1515 /opt/eos/xrootd/bin/xrootd -n mgm -c /etc/xrd.cf.mgm -l /var/log/eos/xrdlog.mgm -Rdaemon
├─1519 /opt/eos/xrootd/bin/xrootd -n mgm -c /etc/xrd.cf.mgm -l /var/log/eos/xrdlog.mgm -Rdaemon
├─1524 /opt/eos/xrootd/bin/xrootd -n mgm -c /etc/xrd.cf.mgm -l /var/log/eos/xrdlog.mgm -Rdaemon
├─1528 /opt/eos/xrootd/bin/xrootd -n mgm -c /etc/xrd.cf.mgm -l /var/log/eos/xrdlog.mgm -Rdaemon
├─1533 /opt/eos/xrootd/bin/xrootd -n mgm -c /etc/xrd.cf.mgm -l /var/log/eos/xrdlog.mgm -Rdaemon
├─1536 /opt/eos/xrootd/bin/xrootd -n mgm -c /etc/xrd.cf.mgm -l /var/log/eos/xrdlog.mgm -Rdaemon
├─1539 /opt/eos/xrootd/bin/xrootd -n mgm -c /etc/xrd.cf.mgm -l /var/log/eos/xrdlog.mgm -Rdaemon
├─1543 /opt/eos/xrootd/bin/xrootd -n mgm -c /etc/xrd.cf.mgm -l /var/log/eos/xrdlog.mgm -Rdaemon
├─1546 /opt/eos/xrootd/bin/xrootd -n mgm -c /etc/xrd.cf.mgm -l /var/log/eos/xrdlog.mgm -Rdaemon
├─1549 /opt/eos/xrootd/bin/xrootd -n mgm -c /etc/xrd.cf.mgm -l /var/log/eos/xrdlog.mgm -Rdaemon
├─1553 /opt/eos/xrootd/bin/xrootd -n mgm -c /etc/xrd.cf.mgm -l /var/log/eos/xrdlog.mgm -Rdaemon
├─1556 /opt/eos/xrootd/bin/xrootd -n mgm -c /etc/xrd.cf.mgm -l /var/log/eos/xrdlog.mgm -Rdaemon
├─1559 /opt/eos/xrootd/bin/xrootd -n mgm -c /etc/xrd.cf.mgm -l /var/log/eos/xrdlog.mgm -Rdaemon
├─1562 /opt/eos/xrootd/bin/xrootd -n mgm -c /etc/xrd.cf.mgm -l /var/log/eos/xrdlog.mgm -Rdaemon
├─1566 /opt/eos/xrootd/bin/xrootd -n mgm -c /etc/xrd.cf.mgm -l /var/log/eos/xrdlog.mgm -Rdaemon
├─1569 /opt/eos/xrootd/bin/xrootd -n mgm -c /etc/xrd.cf.mgm -l /var/log/eos/xrdlog.mgm -Rdaemon
├─1572 /opt/eos/xrootd/bin/xrootd -n mgm -c /etc/xrd.cf.mgm -l /var/log/eos/xrdlog.mgm -Rdaemon
├─1575 /opt/eos/xrootd/bin/xrootd -n mgm -c /etc/xrd.cf.mgm -l /var/log/eos/xrdlog.mgm -Rdaemon
├─1579 /opt/eos/xrootd/bin/xrootd -n mgm -c /etc/xrd.cf.mgm -l /var/log/eos/xrdlog.mgm -Rdaemon
├─1582 /opt/eos/xrootd/bin/xrootd -n mgm -c /etc/xrd.cf.mgm -l /var/log/eos/xrdlog.mgm -Rdaemon
├─1585 /opt/eos/xrootd/bin/xrootd -n mgm -c /etc/xrd.cf.mgm -l /var/log/eos/xrdlog.mgm -Rdaemon
├─1589 /opt/eos/xrootd/bin/xrootd -n mgm -c /etc/xrd.cf.mgm -l /var/log/eos/xrdlog.mgm -Rdaemon
├─1592 /opt/eos/xrootd/bin/xrootd -n mgm -c /etc/xrd.cf.mgm -l /var/log/eos/xrdlog.mgm -Rdaemon
├─1595 /opt/eos/xrootd/bin/xrootd -n mgm -c /etc/xrd.cf.mgm -l /var/log/eos/xrdlog.mgm -Rdaemon
├─1599 /opt/eos/xrootd/bin/xrootd -n mgm -c /etc/xrd.cf.mgm -l /var/log/eos/xrdlog.mgm -Rdaemon
├─1602 /opt/eos/xrootd/bin/xrootd -n mgm -c /etc/xrd.cf.mgm -l /var/log/eos/xrdlog.mgm -Rdaemon
├─1605 /opt/eos/xrootd/bin/xrootd -n mgm -c /etc/xrd.cf.mgm -l /var/log/eos/xrdlog.mgm -Rdaemon
├─1609 /opt/eos/xrootd/bin/xrootd -n mgm -c /etc/xrd.cf.mgm -l /var/log/eos/xrdlog.mgm -Rdaemon
├─1612 /opt/eos/xrootd/bin/xrootd -n mgm -c /etc/xrd.cf.mgm -l /var/log/eos/xrdlog.mgm -Rdaemon
├─1616 /opt/eos/xrootd/bin/xrootd -n mgm -c /etc/xrd.cf.mgm -l /var/log/eos/xrdlog.mgm -Rdaemon
├─1619 /opt/eos/xrootd/bin/xrootd -n mgm -c /etc/xrd.cf.mgm -l /var/log/eos/xrdlog.mgm -Rdaemon
└─1622 /opt/eos/xrootd/bin/xrootd -n mgm -c /etc/xrd.cf.mgm -l /var/log/eos/xrdlog.mgm -Rdaemon

Jul 06 11:19:58 mgm3.spacescience.ro systemd[1]: Starting EOS mgm...
Jul 06 11:19:58 mgm3.spacescience.ro systemd[1]: Started EOS mgm.
Jul 06 11:19:59 mgm3.spacescience.ro xrootd[1007]: Register objects provided by NsQuarkdbPlugin ...
Jul 06 11:20:01 mgm3.spacescience.ro xrootd[1007]: Preparing to start gateway!
Jul 06 11:20:01 mgm3.spacescience.ro xrootd[1007]: Successful after calling run!
Jul 06 11:20:01 mgm3.spacescience.ro xrootd[1007]: Before calling run!
Jul 06 11:20:01 mgm3.spacescience.ro xrootd[1007]: Core gateway start ...

does anyone have an idea about this?

going back (downgrade) to 4.4.7 restored functionality …