Hi Gokmen, welcome to the SonarSource Community!
To start with, SonarQube 6.7.2 is quite old and no longer supported; we recommend you upgrade to at least the 7.9 LTS release or consider migrating all the way to 8.x since the final 8.x release will become the new LTS in a few months. Read our guidance on upgrading before getting started.
Since 6.7.x, we deprecated support for the old .exec JaCoCo report format in favor of XML reports - this took effect in the version of the JaCoCo report importer bundled with SonarQube 7.9 and is fully removed if you update to the latest. I’d recommend you upgrade, update all analyzers, and try this using XML format reports.
We have a number of guides for configuring and troubleshooting JaCoCo coverage issues in our Guides area: