4 days to fit in - Reverse Logistics Motion Industries Employee Review

Was hired for a reverse logistics analyst position (basically processing returns). I worked only for 4 days before I was told that I wasn’t a good fit and was terminated. Within that 4 day training period, the training was very weak and all over the place. I also didn’t have access to software until my third day of employment so any hands on training was towards the latter of the week. Everyone seems happy and all is going swell so I assume there is no issue. Monday morning I’m terminated without any explanation other than “I’m not a good fit”. Exactly what fits in 4 days?