I was having issues downloading video on a Mac using the ReoLink client 3.5.6.55. I tried on two different computers, one running MacOS 10.15 and one running 10.13. On both machines I was having serious issues downloading the video. I might get a few to download, but then it would fail. Sometimes the first video would fail part way through.

I then moved the Mac running 10.13 to a wired connection. This has resolved the issue. I've since downloaded approximately 4 days of video from two cameras without issue over the last two days.

I wanted to share to let others know that if you're having issues, consider moving from wireless to a wired connection.