So I am guessing that either something you copied across has broken it, or you have some network/firewall issue that is blocking the mails.
First thing I'd do is find the email log in /var/log (not sure what it would be called but should be in there) and see if there are any errors. Double check your WordPress config too (I know nothing about WordPress but I assume that there are some settings somewhere in there).
By default the TKL server has email configured
So I am guessing that either something you copied across has broken it, or you have some network/firewall issue that is blocking the mails.
First thing I'd do is find the email log in /var/log (not sure what it would be called but should be in there) and see if there are any errors. Double check your WordPress config too (I know nothing about WordPress but I assume that there are some settings somewhere in there).