/tmp/J_5JHKXU.bin.part could not be saved, because the source file could not be read.
Try again later, or contact the server administrator.
This is actually not a download problem related to the server/site you're using but actually some weird bug with Firefox. I know because no matter what site I tried to download from this error kept happening.
Simpy restarting Firefox was enough to get things working again.
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