1. Back up your nxt-default.properties file in the conf folders.

2. Open nxt-default.properties file and make sure to have this setting this in the Database section:

#### DATABASE ####

# Database connection JDBC url, see the H2 documentation for possible customizations.
# Append ;AUTO_SERVER=TRUE to enable automatic mixed mode access.
# The nxt_db folder is expected to be in the current working directory, will be created if missing.
nxt.dbUrl=jdbc:h2:./burst_db/burst;DB_CLOSE_ON_EXIT=FALSE
nxt.dbUsername= sa
nxt.dbPassword= sa

# Database connection JDBC url to use with the test network, if isTestnet=true
#nxt.testDbUrl=jdbc:h2:./burst_test_db/burst;DB_CLOSE_ON_EXIT=FALSE

nxt.dbMaximumPoolSize=10

# Database connection timeout in seconds.
nxt.dbLoginTimeout=70

# Database default lock timeout in seconds.
nxt.dbDefaultLockTimeout=60

# Maximum simultaneous database connections.
nxt.maxDbConnections=30

# The memory allocated to database cache, in kB.
# If set to 0, defaults to 50 % of the memory available to the JVM.
nxt.dbCacheKB=0