This issue usually presents itself after an interrupted upgrade.
In the logs you’d find entries similar to:
Lenses failed to start... liquibase.exception.LockException: Could not acquire change log lock.
To fix this issue, get console in the host running Lenses and execute the following commands :
java -cp h2/bin/h2-1.4.199.jar org.h2.tools.Shell \
-url 'jdbc:h2:/data/storage/lensesdb;AUTO_SERVER=TRUE' \
-sql 'UPDATE DATABASECHANGELOGLOCK SET LOCKED=0'