It's not typical, but I had the same problem--wanted to watch Upperworld..error message on fire stick, and nothing on pc..same with other older films I tried ...but newer ones were fine, live stream fine...from now on, I'll just record to dvr what I want to watch if the site continues to be plagued with technical problems....
Sadly, I've found problems like this to be all too typical with TCM ON-DEMAND over the years.
I only use a PC for TCM ON-DEMAND viewing (no other devices, nor app's).
As far as I can figure from my end, this latest (of a very long line) of TCM ON-DEMAND "snafu's" began a week ago, Sunday evening (9/10/2017).
Everything from earlier that day, up until the first of the Prime Time movies, seemed to load and play normally from ON-DEMAND.
TCM hadn't aired "Blood and Sand" (1941) since 2/8/2013, and I wanted to watch it again... ON-DEMAND. No such luck.
For several days the movie wouldn't load at all, just a black screen. Then later in the week it would finally load, but began buffering and then freezing completely during Ben's intro.
Now it will load and begin to play, but the buffering begins early on in the first few minutes of the movie, and occurs repeatedly, often completely "freezing" the screen.
Same scenario with "The Three Musketeers" (1921), and "Charulata" (1965).
Strangely, I was able to watch "The Coward" (1965) all the way through without a problem.
I checked all of the usual suspects (latest browser & flash player version, my provider's download stream consistency, my modem, other on-line video sources i.e. YouTube, PBS, etc.), everything was as it should be, except for TCM ON-DEMAND.
I have experienced problems "similar" to this with TCM ON-DEMAND several times before over the last three years, and many times "someone" at the TCM end "eventually" catches the problem and it mysteriously "self-corrects" after a few days... Usually before the particular movies affected run past their 7 day ON-DEMAND window... sometimes not.
Generally all movies during a particular time frame period are affected, which does make this recent problem somewhat different as it appears "sporadic" from Sunday night through to Wed morning (9/10-9/13).
For example, that Sun night "Blackbeard The Pirate" (1952) appeared to load and play "normally" (though I did not watch it through to completely verify), whereas "B&S" immediately before it would not, and neither "T3M" nor "Charulata" after it...
But from "The Coward" through the following Monday's Jimmy Durante marathon, TCM ON-DEMAND movies appeared to load and play normally. However I only verified two of them completely ("Speak Easily" (1932) & "What! No Beer?" (1933), both early Buster Keaton talkies).
Then TCM threw us a curve ball that Monday night and didn't have a single Disney feature available ON-DEMAND, which I wasn't expecting at all since for the last two and a half years every Disney feature was also available for ON-DEMAND viewing.
The ON-DEMAND no load, no play, &/or buffering "problem" began reoccurring again with the Tuesday am (9/12/2017) schedule. Nothing beginning with "Son of the Gods" (1930) through the entire line-up of Jennifer Jones' movies that evening would load or play normally from ON-DEMAND.
However since the Wed am program day began (9/13) every ON-DEMAND movie loads and plays as it should, while the previous ON-DEMAND "failed" titles (from Sunday night-Tuesday night-early Wed am) remain "unviewable."
I noted that the trailers, clips, and intros were not affected. And the Live streams that i checked appeared to load and play normally.
What makes these issues particularly annoying is that when they (frequently) occur we have no effective way to contact anyone at TCM about them (except for ineffectively mentioning the problem/s on these boards).
As previously mentioned by others, TCM obviously doesn't effectively monitor their own ON-DEMAND output, and evidently has no effective (if at all) Q&A or oversight staff.
I've also considered the possibility that the recent hurricane/s may be a factor... this time.
However, because this type of frustrating problem, as well as many others, occur so frequently with TCM ON-DEMAND, I long ago stopped recommending it to anyone that I wanted to retain as a "friend".
I did check and "Blood & Sand" is on next months schedule, so perhaps there will be another "opportunity" to view it then.
Who knows when TCM will re-air the 1921 version of "The Three Musketeers" and Charulata," neither of which I've seen before?