There is some issue on Debian 9 and Ubuntu 18.04 and later. It appears that the clock (the CAPTCHA) has no hands but you can see them outside the clock. You need to compile ImageMagick yourself with librsvg to solve this issue.
Thanks Tmiland for showing up a solution at #299
For lazy people a little hack is to disable CAPTCHA or use text one.
You can check if your version of ImageMagick is affected with
convert -list format.
It should show the following if your installed version is okay.
SVG SVG rw+ Scalable Vector Graphics (RSVG 2.40.13) SVGZ SVG rw+ Compressed Scalable Vector Graphics (RSVG 2.40.13)
If this is not the case your version is not compiled with librsvg, then you get the following.
SVG SVG rw+ Scalable Vector Graphics (XML 2.9.4) SVGZ SVG rw+ Compressed Scalable Vector Graphics (XML 2.9.4)
Follow the steps to fix this issue:
$ sudo apt purge imagemagick
$ cd /tmp # check for new releases: https://github.com/ImageMagick/ImageMagick6/releases $ wget https://github.com/ImageMagick/ImageMagick6/archive/6.9.11-19.tar.gz $ tar -xvf 6.9.10-24.tar.gz $ cd ImageMagick6-6.9.10-24 $ ./configure --with-rsvg $ make $ sudo make install
Set the correct path:
$ sudo ln -s /usr/local/bin/convert /usr/bin/convert
If you get an error here that this file already exists, please execute
$ sudo apt autoremove
convert -list format reports
SVG rw+ Scalable Vector Graphics (RSVG 2.40.16) SVGZ rw+ Compressed Scalable Vector Graphics (RSVG 2.40.16)
Restart Invidious, just to be sure
$ sudo systemctl restart invidious.service