In my taxonomy terms,when I try to edit a term I got this error :
An unrecoverable error occurred. The uploaded file likely exceeded the maximum file size (32 MB) that this server supports.
even though I didn't try to upload a file,I tried to remove the uploaded file. and I don't have mod_security module enable on my server .( as I search through google,there was problem with mod_security apache module and ajax).
I have no idea why this is happening only on particular vocab terms,not in anywhere else.