SQL server stops sending db mails in sql server 2014

Check out if someone disable broker or disable sending e-mail. These two queries should return 1.

SELECT value_in_use
FROM sys.configurations
WHERE name = 'Database Mail XPs';

SELECT is_broker_enabled 
FROM sys.databases 
WHERE name='MSDB';

Is there records in the transmission queue? No record means good. If there is a record, pay attention on field transmission_status. This is written the reason this message is on the queue. This is generally an error message explaining why sending the message failed.

select * from msdb.sys.transmission_queue ;

Try cleaning 'ExternalMailQueue'

WHILE EXISTS
(
    SELECT 'ExternalMailQueue' AS ServiceBrokerQueueName, 
           *
    FROM [msdb].[dbo].[ExternalMailQueue]
)
    BEGIN
        WAITFOR(
        RECEIVE TOP (1) conversation_group_id FROM [ExternalMailQueue]), TIMEOUT 1000;
    END;