When pullRequestService is asked to conflict .......DB error

i use bibucket v6.9.0.

but i have troble .

When pullRequestService is asked to conflict status from pull request ,
i received the answer that "DataStoreException : A database error occureed " and “JDBCConnectionException”.

i wrote this.

pullRequestService.canMerge(request.getRepository().getId(), request.getPullRequest().getId()).isConflicted())

What’s wrong?