Looks like the TelkomSA email servers are on the blink yet again.
Similar to a recent event, messages are currently unable addresses hosting by TelkomSA such @telkomsa.net and @cybertrade.co.za.
There is nothing we can do from our side to correct the problem; this is something that Telkom has to fix on their side. Rest assured that messages will are queued on our servers for the next 24 hours, and delivery will periodically retry automatically.