If you're able to reproduce this behavior using your own email account, that'll help immensely in debugging.
Check the obvious places -- i.e. your spam folder -- to see if the messages are getting trapped there. If so, try viewing the message's headers. Spam filters attach explanations for why they were flagged.
On the server side, see if you can access the mail sending logs. If you're using a local MTA (i.e. you're not using SMTP) these should be somewhere on the machine that OJS is installed on, such as /var/logs/exim/... or similar, depending on that server's mail configuration.
One common problem is recent trends in the adoption of SPF (Sender Protection Framework) rules. OJS 3.0 will include a new approach to email that won't fall on the wrong side of these rules; see http://pkp.sfu.ca/bugzilla/show_bug.cgi?id=8085
Public Knowledge Project Team