Failed to send notification: bad attachment

[YouveGotMeowxy]

In the Web UI I have this in my configuration field:

phpbu=gotify://gotify/A......IV

and then I hop on over to the Notifications tab to try sending a test, and when I do, I get the error in the title. Note that I'm not even trying to send any attachment, just a plain text message to gotify.

Here's a screencast:

I am using APPRISE v1.7.1 in a docker container. Did I somehow screw something up?

[YouveGotMeowxy]

scratch that! I switch to the LSIO container and now it works. :)