E-mail timing out

[fourteen85]

For the last two days I have been getting a message saying that due to inactivity my server has closed the connection, this message seems to be occuring every 5 minutes or so, I click OK on the box and away it goes only to re appear a short time later. I am running outlook 2007 and the e-mail is setup as Imap. The time out box is set at 10 minutes but it always has been and it has never timed out before. is there anything I can do to stop the timing out after a few minutes and leave my outlook open? . thanks