UBB.threads PHP Forum Software Community Forums UBB.threads Version 7/8 Support Emailing posts to multiple addresses

Doesn't work. Can email to a single email address but when I send to more than one nothing gets sent. I tried separating the addresses by commas, semi-colons and spaces but nothing works. Running Ubbthreads 7.3.1.
I can't find any other mention of this in these forums and there doesn't to be any setting relevant under Control Panel so I don't know what is wrong.

I just tested it on 7.5.6 and it worked properly. I'm not sure if there was a change between 7.3.1 and the current build or not. I didn't see anything in the changelogs that specifically address that issue.