Hey there.
It looks like the Java installation being used on your Bitbucket Pipelines runner doesn’t trust the certificate installed on your SonarQube server. This often happens when a self-signed certificate has been installed to serve SonarQube over HTTPS.
If you are using Bitbucket Pipelines hosted runners, you really shouldn’t expect to be able to integrate with services that use a self-signed certificate. Ideally, for integration with cloud CI tools, the SonarQube server should be secured by a Trusted CA Signed SSL Certificate.