SuiteCRM Can't contact LDAP server

hello i have a univention appliance running SuiteCRM which was working ok for months recently i tried to login and i’m getting errors: Can’t contact LDAP server message

does anyone solves this issue? i have read most of the threads about this topic and haven’t found any solution

the service seems to running i tried to reset it few time but it doesn’t solve the issue also when i do netstat -tlpen | grep slapd i get correct ports opened

does anybody have an idea?

thank you