Error: Exception in Users; 'LDAPProps' object has no attribute 'conn_timeout'

[KoalaJas]

I'm getting an error when installing Plone and pas.plugins.ldap.
Installation completes with an error while saving settings: Error:Exception in Users; 'LDAPProps' object has no attribute 'conn_timeout'
How should I fix it.

Plone = 5.2.9
pas.plugins.ldap = 1.8.1
Linux System = ubuntu 18.04 LTS