Even though the Vodafone Ireland domain vodafone.ie has six active MX records, this appears to be a dead email domain, and I suggest you suppress all vodafone.ie addresses from any email lists.
Vodafone appears to have announced this closure in 2014. The original announcement no longer appears to be online (nor in the Internet Archive), but here's a discussion forum thread on the topic. Based on this information, it appears that email service for the vodafone.ie domain ceased on October 18, 2014.
None of the six MX servers is responding to connections after repeated testing.
Vodafone New Zealand similarly shut down their email service in 2017.