Role Mapping Error

I have some basics knowledge in linux commands and entry level in security.
I just started working in Kibana. I’m facing a error when i add user and commit them.

Command: /usr/share/elasticsearch/plugins/search-guard-6/tools/ -cd /usr/share/elasticsearch/plugins/search-guard-6/sgconfig -icl -nhnv -cert /etc/elasticsearch/certs/adminuser.pem -key /etc/elasticsearch/certs/adminuser.key cacert /etc/elasticsearch/certs/root-ca.pem -keypass xxxxx@xxx

Error: will update ‘sg/rolemapping’ with /usr/share/elasticsearch/plugins/search-guard-6/sgconfig/sg_roles_mapping.yml
Fail: configuration for ‘rolemapping’ failed beacuse of SettingsException[Failed to load settings from [dummy.json]]; nested: ParsingException[Failed to parse object: expecting token of type [START_OBJECT] but found [[VALUE_STRING]];

Note: I could figure out that this is a configuration syntax error. But i’m unable to figure it out.
Thank you. Have a great day.

When executing the sgadmin command, sgadmin would read the configuration file from this directory:

What files do you have in this directory? Can you post your sg_roles_mapping.yml, please? Also, what does dummy.json refer to? The config files have to be in YAML format, not JSON.