Thanks Ralf for your help. This problem is solved.
Now I can add connections to Guacamole but my home page is still empty.
I found this page :
Where I read this :
The app requires accounts stored in SQL. A workaround for using LDAP or ActiveDirectory for account storage (not just authentication), is to regularly use setup to migrate users and groups to SQL.
Is it always true ? If it’s true, this my be an other problem for me.
My accounts and contacts are stored in LDAP since a long time. I can’t remember why I need to transfer SQL to LDAP. Perhaps to share contacts between accounts ?
LDAP is a black box for me, do you think I can expect to go back to SQL ? Can I transfer easily my accounts and contacts from LDAP to SQL ?