I suspect you've got an over-zealous firewall that's dropping requests with certain types of content; for example, I once encountered a firewall that would drop any request containing the words "delete" and "from" in that order in a misguided attempt to avoid certain types of SQL injection attacks; this sequence appears legitimately in several OJS pages. If you can, try disabling the firewall temporarily to see if that corrects the problem. Then you'll have to do a little legwork to narrow down the specific firewall rule that's causing the trouble.
Open Journal Systems Team
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