I have this kind of problem with the mail queue that has already occurred to me a few times in about 2 months. Sometimes it happens that if I send an email, with two or more recipients in the message, the message is instantly delivered to addresses outside the server, while it remains in the queue for a long time for those belonging to domains inside the server. The only thing I noticed then that if I restart the clamd service, the internal ones are also delivered without further intervention, then everything works correctly for another 2 or 3 weeks without problems until it returns to appear. I am not an expert on clamav or exim and from logs I have not noticed strange things that can make me think of problems, I wanted to know if anyone has ever faced a similar problem or if someone can tell me what is good to look to analyze and solve the problem.

Thanks in advance