Thanks Iguinn, I tried this. But I found no other option. Seems that Splunk don't want "free" user request and participate on experience with the Software without contract. That's what Splunk support page told me after login:
Submit a Case
It appears you do not have an active Support Contract or entitlement and as a result, cannot open a Support case. If you believe this is an error, please contact 1-855-SPLUNK S, or consult https://www.splunk.com/en_us/about-us/contact.html#customer-support for a country specific Support phone number and we can resolve any contractual data integrity issues.
All users are welcome to post questions and answers to https://answers.splunk.com/
If you would like to purchase a Support contract, please consult your local sales person who can be found at https://www.splunk.com/en_us/about-us/contact.html#sales
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