I changed the IP Address of a domain hosted on a Plesk server and, after a couple of hours, everything seemed to point to the right place and the site was loading fine. When I woke up this morning, however, things seem to be pointing back to the original IP on my laptop (but it's still loading correctly on my phone). It's been a full 24 hours since I made the change. I'm just confused because it was working fine for half a day, and now on some connections seems to have reverted back to the old IP.
What are the most logical next steps for troubleshooting this? The DNS records all point to the new IP (via the A Record). Is this just a weird propagation issue with my ISP (meaning I should wait it out) or is there anything I can do to investigate?