I had a number of 412s but it was an issue with the web server, attempting to block spam but being overzealous. It sounds like you have (had) a different problem though I've not come across the server giving out 412 errors for this thing.
Anyway, just in case anyone surfs here searching for 412 Precondition Failed error solutions, when it's to do with 'naughty' words in either the referring or the target URL, etc. I solved it (on Textdrive servers) by putting the following directive in my .htaccess file:
SecFilterEngine Off
It means that spam attacks are potentially more likely but it does stop whatever rules a host has built in at server level.
Not sure if this comment was helpful at all but there you go...
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Anyway, just in case anyone surfs here searching for 412 Precondition Failed error solutions, when it's to do with 'naughty' words in either the referring or the target URL, etc. I solved it (on Textdrive servers) by putting the following directive in my .htaccess file:
SecFilterEngine Off
It means that spam attacks are potentially more likely but it does stop whatever rules a host has built in at server level.
Not sure if this comment was helpful at all but there you go...