It is by now well established that telecollaborative exchanges frequently end in "failed communication" and do not automatically bring about successful negotiation of meaning between the learners. Instead, the intended pedagogic and linguistic aims of online interaction are repeatedly missed, and projects may end in low levels of participation, indifference, tension between participants, or a negative evaluation of the partner group or their culture. The reasons offered in the literature are rather diverse in nature, and there has so far been no attempt to offer a comprehensive overview of such areas of dysfunction. Starting from a review of the existing body of research, this paper develops a structured inventory of factors which may lead to cases of failed communication in online exchanges. In sum, 10 different factors are suggested at four different levels: individual, classroom, socioinstitutional, and interaction. Examples of communication failure taken from two exchanges will be used to illustrate how these factors are interconnected and influence each other. It is concluded that a more discriminating perspective of such problem areas, both among the tutors and the students, can help to further increase intercultural awareness and lead to a better understanding of the dynamic nature of online communication. (Contains 1 figure and 4 notes.)