Please provide dump of LDAP entry of the client you created:
1. Open the client's properties in web UI and copy its "Inum" value
2. Move into Gluu's container
3. Put your LDAP password in `/tmp/.dpw` (it's the same as default admin's password was right after installation)
4. Dump the client's properties: `# /opt/opendj/bin/ldapsearch -h 127.0.0.1 -p 1636 -s sub -T -Z -X -D 'cn=directory manager' -j /tmp/.dpw -b 'o=gluu' -z 3 '&(objectclass=oxauthclient)(inum=YOUR_INUM)'`
5. Share it here. You may decide to remove client's secret from output
Then please move to web UI and increase oxAuth's logs' verbosity level to "DEBUG" as decribed in [this doc](https://gluu.org/docs/ce/3.1.4/operation/logs/), reproduce your issue again and provide us your `oxauth.log` with detailed trace related to this interaction.