But I'm only logged in to one machine, the one giving the error. There is no option/button for "logout of all other concurrent logins" or to set inactive timeouts. Can the website please be updated to add this feature?

I don't understand the problem. Can you explain it further?

When I press "Play" on the DeathTrap video, a pop-up says that I have reached my max device limit. It was playing earlier and the streamer crashed on my computer. After restarting the browser I was unable to resume playing as Vimeo thinks the previous session is still active. Does that make sense?

Ah. Now I see. Try clearing your cache, delete all cookies for your browser. If that does not fix it, you can contact Vimeo and I am sure they will sort things out.
https://vimeo.com/help/contact

Yea, I did those things and tried contacting Vimeo. They are auto-response only, thus the forum. This is not the first time vimeo has done this with Farsight videos, is been a problem for years, that is part of why I've not purchased Farsight videos in years.

I've tried other browsers, other machines, and my phone. All return the same error message.

I'm in hopes that you have a better way to contact Vimeo than their help page.

I'm also having big problems with the Vimeo platform Farsight uses as I stated in another thread.
https://farsight.vhx.tv/forums/general/37988-slow-streaming-and-freezing-videos-problems
Vimeo are definitely not the best when it comes to support, well that's my experience.
I've kind of given up on this. I have purchased all but a couple of Farsight's projects through Vimeo in the past, no issues at all as with all other streaming services. So why this platform has issues, I have no idea.

Mark Read, I hear you. But I can't replicate the problem, and I have tried. I used my ATT Uverse connection, which has a 28 Mbps download speed, which should be slower than your connection. But my playback is smooth. I am looking at it right now. I am watching it at 1080p. I know this information will not please you. These things can be really vexing. For your information, our service is run by Vimeo, and they use Amazon Web Services to stream the videos. So none of this is being done by our own servers. I wish I had a better answer for you.

After some digging, I found the crash problem: the browser was using the "temp" folder but there wasn't enough space. Vimeo indicated they are looking at adding an option to allow end users to clear disconnected session; though, at the moment it can only be done by customer service. An additional item, not a problem, just odd - when viewing the videos, the 4 core processor uses about 65% ~ 85% of it's capacity even though the video hardware and drivers are up-to-date. It seems to be dropping video frames to keep the streams synchronized. When viewing other video sources in 1920*1080 in MP4 format, the CPU run at 13%. Netflix peaks at 22%. Internet speed tests show a regular 28~29 Mbps. Logging out of the session rather than just closing the browser has helped too.