Adobe Campaign classic ldap integration issues

Hi,

We are implementing Adobe Campaign classic v7 on-premise and are facing issues with our ldap integration. When users try to login through client we are facing this error message

'xsv-350012 Invalid login or password. Connection denied'

We have a working lower environment for Adobe Campaign with same ldap settings and it is working fine there.

For this higher environment we have gone through this so far,

- Double checked ldap settings (service account credentials, dn, cn, server, ports etc).

- AD groups attributed to correct users/operators and groups are existing in Adobe Campaign.

- Verified AD server is reachable using port 389 from Adobe Campaign application server.
- Verbose logging, gave nothing.
- AD logs, only shows service account logon success but user authentication is not in the logs.
- We have tried adding operator first, with ldap enabled. But with same results.

- Security zones is not an issue. It is working to login with local user from same network.

Any ideas what more we could look into?

Thank you in advance,

Mattias