[181217-1242 GMT/UTC] Just reporting you that upload to default asciinema server fails by reporting error:
asciinema: upload failed: The server is having temporary problems. Try again in a minute.
asciinema: retry later by running: asciinema upload [FILENAME].cast
I have the same problem - all day today
asciinema: recording finished
asciinema: press <enter> to upload to asciinema.org, <ctrl-c> to save locally
asciinema: upload failed: The server is having temporary problems. Try again in a minute.
asciinema: retry later by running: asciinema upload /var/folders/4k/h9xhvv6j1yg6dzncz3r5s1x80000gn/T/tmpgork_h0z-ascii.cast
Richards-MacBook:vaultssh richardmauri$ ls -lh /var/folders/4k/h9xhvv6j1yg6dzncz3r5s1x80000gn/T/tmpgork_h0z-ascii.cast
-rw------- 1 richardmauri staff 29K Dec 17 20:05 /var/folders/4k/h9xhvv6j1yg6dzncz3r5s1x80000gn/T/tmpgork_h0z-ascii.cast
That was server-side issue - disk full on load balancer node (too much logs, what else, right? 
).
I’ve now set up log rotation and freed disk space, should be good.
Sorry for the inconvenience!
[190416-2032 GMT/UTC] Just reporting you that upload to default asciinema server fails by reporting error:
asciinema: upload failed: The server is having temporary problems. Try again in a minute.
asciinema: retry later by running: asciinema upload [FILENAME].cast$ asciinema upload /tmp/tmpmgbjac3p-ascii.cast
asciinema: upload failed: The server is having temporary problems. Try again in a minute.
asciinema: retry later by running: asciinema upload /tmp/tmpmgbjac3p-ascii.cast