Why is my transaction rolled back unexpectedly?

In our project, we are trying to get code that is currently deployed on WebSphere working on Liberty instead.

After receiving a message an MDB calls a method in a service which inserts the data into a DB2 database.

The problem is that when flush is called, we get the following errors in the log:

javax.persistence.TransactionRequiredException: no transaction is in progress
        at org.hibernate.jpa.spi.AbstractEntityManagerImpl.checkTransactionNeeded(AbstractEntityManagerImpl.java:1136) ~[hibernate-entitymanager-5.1.3.Final.jar:5.1.3.Final]
        at org.hibernate.jpa.spi.AbstractEntityManagerImpl.flush(AbstractEntityManagerImpl.java:1297) ~[hibernate-entitymanager-5.1.3.Final.jar:5.1.3.Final]

[ERROR   ] WLTC0017E: Resources rolled back due to setRollbackOnly() being called.

There are no other errors, like SQL query not being correct or something like that.

Since this code is working fine in WebSphere, I'm wondering if there is something wrong in the configuration or if Liberty does something different in handling transactions.

Below are the relevant pieces of code and configuration:

@Service
public class IdentificationService implements IIdentificationService {

    @Autowired
    private IIdentificationDAO identificationDAO;

    @Transactional
    public Identification insertIdentificationData(RequestForIdentificationRequest request, String referenceNumber) {

        final Identification identification = new Identification();
        ...

        identificationDAO.create(identification);

        LOGGER.debug("Identification record saved with id: {}", identification.getId());
        return identification;
    }
}

@Repository
public class IdentificationDAO extends BaseDAO implements IIdentificationDAO {

    @Override
    public void create(final Identification identification) {
        insertRecord(identification);
    }
}

public abstract class BaseDAO
{
    @PersistenceContext(name = "UserData", unitName = "UserData")
    private EntityManager em;

    /**
     * @param record
     */
    public <T> void insertRecord(final T record)
    {
        em.persist(record);
        em.flush();
    }
}

public class Identification implements Serializable {

    @Id
    @Column(name = "ID")
    @GeneratedValue(strategy = GenerationType.SEQUENCE, generator = "sequenceGenerator")
    @SequenceGenerator(sequenceName = "IDENTIFICATION_SEQ", name = "sequenceGenerator", allocationSize = 1)
    private Long id;
    ...
}

applicationContext.xml

    <jee:jndi-lookup id="userDataSource" jndi-name="jdbc/userdataDB" />

    <bean id="userDataEntityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
        <property name="persistenceUnitName" value="UserData" />
        <property name="persistenceXmlLocation" value="classpath:persistence-userdata.xml" />
        <property name="dataSource" ref="userDataSource" />
        <property name="jpaVendorAdapter">
            <bean class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
                <property name="showSql" value="true" />
                <property name="generateDdl" value="false" />
                <property name="databasePlatform" value="org.hibernate.dialect.DB2Dialect" />
            </bean>
        </property>
        <property name="loadTimeWeaver">
            <bean class="org.springframework.instrument.classloading.InstrumentationLoadTimeWeaver" />
        </property>
    </bean>

    <bean id="transactionManager" class="org.springframework.orm.jpa.JpaTransactionManager">
        <property name="entityManagerFactory" ref="userDataEntityManagerFactory" />
    </bean>

server.xml

    <library id="DB2JCCLib">
        <fileset dir="/etc/liberty/jdbc" includes="db2jcc4.jar, db2jcc_license_cisuz.jar, db2jcc_license_cu.jar"/>
    </library>

    <dataSource id="UserDB" jndiName="jdbc/userdataDB" type="javax.sql.XADataSource"
        isolationLevel="TRANSACTION_READ_COMMITTED">
        <jdbcDriver libraryRef="DB2JCCLib" javax.sql.XADataSource="com.ibm.db2.jcc.DB2XADataSource"/>
        <properties.db2.jcc serverName="${datasource.userdb.serverName}" portNumber="${datasource.userdb.portNumber}"
            databaseName="${datasource.userdb.databaseName}"
            user="user" password="password"/>
    </dataSource>

UPDATE: The problem turned out to be multiple transaction manager beans (named the same) in the configuration pointing at different databases.
Giving them unique names and referring to them explicitly in the Transactional annotation did the trick