@Chefkeks specifically asked you if you had any errors in your PHP log.You would also probably want to check your MySQL logs and Apache (webserver) logs to see if you can get more information than just "Unable to post the message. Try again". Checking all those logs may provide us with an error message that is actually usable.Also , since you have modified your version of osT I would recommend that you 1. back up your site and DB. 2. Install the stock version that your running now and see if you have the issue.If you do, then then you have ruled out your alterations as the cause.We always recommend upgrading to people who are not running current. You should really consider upgrading to a newer version as that one is pretty dated at this point .