Probably a usual issue:

Where are my emails that I have not deleted?! 60 days after I have received an email it is moved from the mailbox and stored in my archive (which is located on the server).

My archive contains messages since I started my current job. However, all emails from a certain period of 5 months (an intermediate period) have disappeared. I have definitely never deleted a single email from my archive!

Please, could you provide me any advice? I am not experienced in networks, servers and stuff like that. I am encountering problems at work and the email history is of great significance!
I am using groupwise version 7.0

I would be grateful for your assistance.