Thread:Project:Support desk/Unknown error in PHP's mail() function/reply (2)

The solution was to remove a line from the PHP configuration file that was redundantly calling a PHP module that was already called from a different config file. Sorry I don't have the specifics at hand right now. Advice to others that have this problem: try sending mail from the CLI, if you get an error, fix that and then try sending from your wiki again. Thanks Florianschmidtwelzow for the help.