Two points to consider:
1. If you notice on your reports there are two ▶ links for each recording, the first one contains an IP based link, the second one has a FQDN based link. Depending on what pc and what location you are opening the report from, the first link might not work, but the second one should work.
View attachment 9614
2. Also as Stefan pointed out, the link to the recording is written at the time the call is made (not at the time the report is generated).
Founded in 2005, when VoIP was an emerging technology, 3CX has gone on to establish itself as a global leader in business communications.