SonarQube 9.9.4 LTS, 9.9.1 LTS
SonarQube is deployed by zip,
We are using SonarQube for two years. From this year February we have encountered this error. After investigation the root cause of the problem is the CloudFlare WAF managed-rule of OWAPS Inbound Anomaly Score Exceeded. After allowing an exception for this service, everything is backed to normal.
This work takes 2 months to discover. FYI