After license server (Linux) reboot license daemon won't restart

Hello

Historic:

We had 3 redondant license servers up and running. Last monday one of them rebooted and the restart auto or manual don't works.
- alterad: 11.18.2.0

- and Flexlm: 11.18.1.0

With this error message :
... Searching license files
... Processing license file /sw/licenses/altera/gnx6051.lic
lmutil - Copyright (c) 1989-2021 Flexera. All Rights Reserved.
Flexible License Manager status on Tue 1/10/2023 15:53

License server status: 1800@gnx6051,1800@gnx6052,1800@10.131.114.8
License file(s) on gnx6051: /opt/licenses/altera/gnx6051.lic:

gnx6051: license server UP (MASTER) v11.18.1
gnx6052: license server UP v11.18.1
10.131.114.8: Cannot connect to license server system. (-15,570:115 "Operation now in progress")

Vendor daemon status (on gnx6051):

alterad: UP v11.18.2

End license stat procedure

All attempts to restart directly on the server failed with this error message:

Entering license start procedure
...... Processing license file
...... Setting ulimit to 8192
...... Saving debug log file /opt/licenses/log/altera/gnx6051.dl
...... Using LMGRD /opt/licenses/flexlm/bin/lmgrd_11.18.1.0
...... With arguments: -2 -p -x lmdown -reuseaddr
...... Starting lmgrd ...
/opt/licenses/flexlm/bin/lmgrd_11.18.1.0 -2 -p -x lmdown -reuseaddr -c /opt/licenses/altera/gnx6051.lic -l /opt/licenses/log/altera/gnx6051.dl
End license start procedure
licmgr@gnx6053 > lic_stat -v altera
... Searching license files
... Processing license file /opt/licenses/altera/gnx6051.lic
lmutil - Copyright (c) 1989-2021 Flexera. All Rights Reserved.
Flexible License Manager status on Tue 1/10/2023 17:07

License server status: 1800@gnx6051,1800@gnx6052,1800@gnx6053
License file(s) on gnx6051: /opt/licenses/altera/gnx6051.lic:

lmgrd is not running: Cannot connect to license server system. (-15,570:115 "Operation now in progress")
End license stat procedure

I noted that flexlm was 11.18.1.0 and I updated to 11.18.2.0 but when I stoped/started the 3 redondant license servers never restarted.

all return this error:
/tmp/lmgrd.new -2 -p -x lmdown -reuseaddr -c /opt/licenses/altera/gnx6051.lic -l /opt/licenses/log/altera/gnx6051.dl
17:48:39 (lmgrd) -----------------------------------------------
17:48:39 (lmgrd) Please Note:
17:48:39 (lmgrd)
17:48:39 (lmgrd) This log is intended for debug purposes only.
17:48:39 (lmgrd) In order to capture accurate license
17:48:39 (lmgrd) usage data into an organized repository,
17:48:39 (lmgrd) please enable report logging. Use Flexera's
17:48:39 (lmgrd) software license administration solution,
17:48:39 (lmgrd) FlexNet Manager, to readily gain visibility
17:48:39 (lmgrd) into license usage data and to create
17:48:39 (lmgrd) insightful reports on critical information like
17:48:39 (lmgrd) license availability and usage. FlexNet Manager
17:48:39 (lmgrd) can be fully automated to run these reports on
17:48:39 (lmgrd) schedule and can be used to track license
17:48:39 (lmgrd) servers and usage across a heterogeneous
17:48:39 (lmgrd) network of servers including Windows NT, Linux
17:48:39 (lmgrd) and UNIX.
17:48:39 (lmgrd)
17:48:39 (lmgrd) -----------------------------------------------
17:48:39 (lmgrd)
17:48:39 (lmgrd)
17:48:39 (lmgrd) Server's System Date and Time: Tue Jan 10 2023 17:48:39 CET
17:48:39 (lmgrd) lmdown requests disabled
17:48:39 (lmgrd) Unsupported license file encoding. Please ensure /opt/licenses/altera/gnx6051.lic is either ASCII or UTF-8 encoded.
17:48:39 (lmgrd) No license file found with supported format and encoding

I never modified license file and after 6 hours of license down, the reload works and without understand why.

... Searching license files
... Processing license file /opt/licenses/altera/gnx6051.lic
lmutil - Copyright (c) 1989-2021 Flexera. All Rights Reserved.
Flexible License Manager status on Wed 1/11/2023 00:25

License server status: 1800@gnx6051,1800@gnx6052,1800@gnx6053
License file(s) on gnx6051: /opt/licenses/altera/gnx6051.lic:

gnx6051: license server UP (MASTER) v11.18.2
gnx6052: license server UP v11.18.2
gnx6053: license server UP v11.18.2

Vendor daemon status (on gnx6051):

alterad: UP v11.18.2

End license stat procedure

Since this is the second time I have encountered this problem,
I want to find the root cause (at least understand why I had to wait a long time to restart the alterad daemon) ?

How I send you private message for license file?

I share with you:

- /var/log/messages of gnx6053

- sceenshots during restart of triad license servers (client and server)

- OS on license servers Virtual Machine Redhat 7.9

- Quartus version used 22.4

Regards
Cedric