I noticed this happening regularly in mailbox.log
2019-04-16 19:39:08,244 WARN [ZxLink Handler Thread] [] extensions - Exception ZxLink: com.google.inject.ProvisionException: Unable to provision, see the following errors:
1) null returned by binding at com.zextras.modules.mobile.v2.engine.actions.factories.SyncItemEmitterFactory.create()
but the 6th parameter of com.zextras.modules.mobile.v2.engine.actions.utils.SyncItemEmitter.(Unknown Source) is not @Nullable
at com.zextras.modules.mobile.v2.engine.actions.factories.SyncItemEmitterFactory.create(Unknown Source)
while locating com.zextras.modules.mobile.v2.as.encoders.AsWriter annotated with @com.google.inject.assistedinject.Assisted(value="")
for the 6th parameter of com.zextras.modules.mobile.v2.engine.actions.utils.SyncItemEmitter.(Unknown Source)
while locating com.zextras.modules.mobile.v2.engine.actions.utils.SyncItemEmitter annotated with @com.google.inject.internal.UniqueAnnotations$Internal(value=1)
1 error
at com.google.inject.internal.InternalProvisionException.toProvisionException (InternalProvisionException.java:226)
at com.google.inject.internal.InjectorImpl$1.get (InjectorImpl.java:1053)
at com.google.inject.assistedinject.FactoryProvider2.invoke (FactoryProvider2.java:836)
at com.sun.proxy.$Proxy145.create (null:-1)
at com.zextras.modules.mobile.v2.engine.actions.CollectionSyncAction.execute (CollectionSyncAction.java:111)
at com.zextras.modules.mobile.v2.engine.actions.remote.RemoteActionParserImpl.handleRemoteAction (RemoteActionParserImpl.java:93)
at com.zextras.modules.mobile.ZxLinkMobileHandlerImpl.execZxLink (ZxLinkMobileHandlerImpl.java:79)
at com.zextras.modules.mobile.MobileModule.execZxLink (MobileModule.java:98)
at com.zextras.lib.ZELinkHandler.execZxLink (ZELinkHandler.java:57)
at com.zextras.lib.ZELinkHandler.run (ZELinkHandler.java:112)
at com.zextras.lib.activities.ActivityThread.run (ActivityThread.java:144)
Release 8.8.12.GA.3794.UBUNTU16.64 UBUNTU16_64 FOSS edition, Patch 8.8.12_P1 proxy.
Zextras 2.16.0