The most common download error happens when people forget to change "www" to"dl" in the download address of dropbox. to correct that, for example: https://www.dropbox.com/s/****************/ <level name>.zip?dl=0 will not work unless you replace www with dl for example https://dl.dropbox.com/s/****************/ <level name>.zip?dl=0
Change https://www.dropbox.com/s/****************/<Level name>.zip?dl=0 to https://dl.dropbox.com/s/****************/<Level name>.zip?dl=0 then technic launcher download error will be fixed. Same may apply for mediafire. if rar file doesn't wirk, try using zip files.
