Service broker/Sqldependency errors from server log

I am using service broker/Sqldependency to monitor table changes. Actual console application runs as windows service on a server different than the sql server. We stop and start the service everyday. Its working fine other than the two errors happening everyday

First error corresponds to the time that we stop and start the windows service which in tern stops and starts the sqldependency

Service Broker needs to access the master key in the database 'XXXX'. Error code:32. The master key has to exist and the service master key encryption is required.

Second error corresponds to the timeframe when the first change happens in the table after  stop and start of sqldependency

The query notification dialog on conversation handle '{4443C789-1047-E511-80DA-005056A32BA6}.' closed due to the following error: '<?xml version="1.0"?><Error xmlns="http://schemas.microsoft.com/SQL/ServiceBroker/Error"><Code>-8490</Code><Description>Cannot find the remote service &apos;SqlQueryNotificationService-555c9c9d-d01a-423c-8710-7e9e9a63fbca&apos; because it does not exist.</Description></Error>'.5

Following is the code snippet I am using

OnService Start:

SqlDependency.Stop(connectionString);
SqlDependency.Start(connectionString);

OnService Stop

SqlDependency.Stop(connectionString);

In notification event

 SqlDependency dependency = new SqlDependency(command);
dependency.OnChange += new OnChangeEventHandler(OnDependencyChange);

I am not sure what else I am missing that's causing the above listed errors. Could someone please help me to understand Whats causing these errors and whats the resolution. The service seems to be running fine other than these two errors everyday.

Appreciate your time and reply