Hangfire equee not work

We are using Hangfire with PostgresSql and sometimes, the HangFire dashboard shows that there are some jobs (X) Enqueued (Queues X/3), but going not works and not show error.

error in my logs

ERROR 2019-08-15 10:16:55,839 [er #1] Hangfire.Processing.BackgroundExecution - Execution DelayedJobScheduler is in the Failed state now due to an exception, execution will be retried no more than in 00:00:04
Hangfire.PostgreSql.PostgreSqlDistributedLockException: Could not place a lock on the resource ‘HangFire:locks:schedulepoller’: Lock timeout.
at Hangfire.PostgreSql.PostgreSqlDistributedLock.PostgreSqlDistributedLock_Init_Transaction(String resource, TimeSpan timeout, IDbConnection connection, PostgreSqlStorageOptions options)
at Hangfire.PostgreSql.PostgreSqlDistributedLock…ctor(String resource, TimeSpan timeout, IDbConnection connection, PostgreSqlStorageOptions options)
at Hangfire.PostgreSql.PostgreSqlConnection.AcquireDistributedLock(String resource, TimeSpan timeout)