LDAP issues where the LDAP Server return multiple values for one attribute

I got the following error message when i try to configure LDAP authentication.

I use the latest version.
Any Ideas ?

And by the way i can't change the LDAP layout.

Hi @timmel
Please post "Diagnostic Info" from Admin > Troubleshooting.
What do you mean by "can't change the LDAP layout" ?

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"name": "H2 JDBC Driver",
"version": "1.4.197 (2018-03-18)"
"run-mode": "prod",
"version": {
"date": "2021-05-27",
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LDAP layout -> LDAP schema

@timmel Metabase requires that you return a single string in firstname, lastname and email.
Latest release is 0.39.4

@timmel You can set base search and attribute in the configuration:

ok let me look for other LDAP attributes in the schema

I found other attributes and now it works.
Thanks for your time !