A weak internet connection could cause an email to not be sent, therefore preventing the individual from communicating via email with the recipient. If you worked for Microsoft and your job involved sending a lot of emails to lots of different people who were relying on you to send them information, a weak connection could be a major problem. To overcome this communication barrier the individual could move closer to the internet router to achieve a stronger connection. They could also switch to another computer that is closer to the router which would receive a better connection. This way you would be able to send your emails due to the stronger connection. This would then allow effective online communication to be achieved.
As well as a weak connection, no connection at all would also prevent you from communication online via webcam, instant messaging or emails. To overcome this barrier to communication you could check that all the wires are properly connected up to allow internet connection if you are at home. If they are and this does not solve the problem you could ring up the supplier of your internet router. If you were working for a company and the internet went down you would have to contact an IT technician and get them to fix it. All of these solutions will eventually establish effective online communication once more.