Finally, The solution that worked for me is Adding a new security test, with the same realm, and with type mobileSecurityTest
<mobileSecurityTest name="MyPushSecurityTest">
<testUser realm="MyAuthRealm"/>
<testDeviceId provisioningType="none"/>
</mobileSecurityTest>
I think that this should be added to the current Worklight documentation, or a bug report must be opened.
Thank you all for your help.