The reasons why an IVF cycle can be cancelled are varied. For example, being a poor responder or at risk of developing Ovarian Hyperstimulation Syndrome (OHSS) are common causes.
Another IVF cancellation reason is the inability of the male partner to provide the sperm sample. In some cases, either due to performance anxiety, he is unable to ejaculate on the day of egg retrieval for IVF. Without a sperm sample, the eggs retrieved should be frozen for later use.
It is also possible that the sperm sample contains poor-quality sperms, or that it doesn't contain sperm at all (zero sperm count or azoospermia).
Finally, in case you are going to use sperm that has been through the freezing-thawing process, it is possible for the quality of samples to be reduced post-thaw, which would affect severely the quality of sperm.