Actually, Sevilla's failure in the Champions League was predictable by looking at their performance in La Liga. In La Liga alone they have only recorded 2 wins from the 16 matches they have played, so I'm not too surprised when in the Champions League they didn't even win once.
Sevilla's decline is obvious, so it's not unusual for them not to be able to place at least in the Europa League this season. The managemen must totally evaluate the team, as they are also in danger of being relegated this season. They are 16th with 13 points, the same points that 18th-placed Cadiz have. That's certainly not good for a club that is known to be good in the Europa League, and they are even the club that has won the most titles there.
I had predicted that Sevilla would fight hard in the last match against Lens to get third place in the group phase so they could play in the European league, but they failed and were only able to control the match without being able to maximize the opportunities that has into a goal. It's quite strange to see that they are not in the European league, but seeing how bad their performance is, it is very possible that in the European league, if they manage to qualify, they will have bad luck because this season there are several teams that are stronger than last season, and having been eliminated in the European competition, they should be able to improve their position in La Liga is only in 16th position.