mailgun email stops after few hours

[fireball003]

Hi,
I have setup mailgun as email service provider from Admin >> settings >> Email >> SMTP Transport. It works perfect for few hours (number of hours yet to determine), but stops working after few hours. When I save the mailgun credentials again, it starts working and same thing happens after few hours.

What might be the reason behind this issue? How to solve this issue?

[PitaJ]

Are there any errors in the server logs?

[scottalanmiller]

If you go to MailGun's site, there might be information there.