liquibase lock error while starting ReadyAPI

Hi,

while starting ReadyAPI workbench I'm getting following error message:

ERROR [LiquibaseDbInitializer] Failed to initialize database
liquibase.exception.LockException: Could not acquire change log lock. Currently locked by ... (ip-address) since 2016-05-19 07:58

at liquibase.lockservice.StandardLockService.waitForLock(StandardLockService.java:174)
at liquibase.Liquibase.update(Liquibase.java:186)
at liquibase.Liquibase.update(Liquibase.java:181)
at com.smartbear.ready.db.init.liquibase.LiquibaseDbInitializer.initdb(LiquibaseDbInitializer.java:38)
at com.smartbear.ready.db.init.liquibase.LiquibaseDbInitializer$$FastClassByGuice$$2a5f2037.invoke(<generated>)

...

How can I get rid off this failure or existing lock?

Thanks in advance,

/Ronald