"[Error] undefined" and "500 Internal Server Error" when using rotation

[Seudo3]

Using rotation produces a "[Error] undefined" error when previewing with some files.

• Load "Jean Petithuguenin Une Mission dans la Lune 1926.djvu", page 3, with CropTool: https://croptool.toolforge.org/?bottom=&height=&left=&page=3&ratio=&right=&site=commons.wikimedia.org&title=Jean+Petithuguenin+Une+Mission+dans+la+Lune+1926.djvu&top=&width=

• Select something and rotate it, e. g. Top:1219, Left:1262, Width:5718, Height:3446, Rotation:-2, Aspect ratio: Free

• Then click "Preview".

The following message appears (in red): [Error] undefined

When I check the network flow (Firefox 91.4.0esr), I can see the following request:

URL: https://croptool.toolforge.org/api/file/crop?height=3446&method=precise&page=3&rotate=-2&site=commons.wikimedia.org&title=Jean+Petithuguenin+Une+Mission+dans+la+Lune+1926.djvu&width=5718&x=1262&y=1219
State: 500 Internal Server Error

Apparently, this error does not occur when rotating 90° (see https://commons.wikimedia.org/wiki/Commons_talk:CropTool/Archive_2#Rotation). A screenshot is also available at https://commons.wikimedia.org/wiki/File:Croperrorundefined.png

Thanks for developing this tool!