"In general, the Internet was not designed to accommodate deliberate failures to communicate"

This quote by Daniel J. Bernstein is describing the truth that the Internet was not designed to manage scenarios where interaction is intentionally avoided. This could be deliberate, such as when somebody is trying to conceal info or avoid contact with another person. It could also be unintentional, such as when somebody is unable to access the Internet due to technical difficulties. In either case, the Internet was not developed to manage these kinds of circumstances, and as a result, communication can be challenging or perhaps difficult. This quote acts as a tip that the Internet is not constantly trusted and that interaction should be taken seriously. It also highlights the significance of having a backup plan in case of technical troubles or other problems that could avoid interaction.