Plugin not activating giving 500 internal error

[ZahidServers]

Getting error while activating plugin with my basic reseller plan I asked GoDaddy support but they had no idea on this issue is it due to I have already launched the site using GoDaddy's default way of reseller here webaon.com my site, if so then how I undo it and do it using WordPress again. Note I have uninstall and install WordPress many times and flushed caches opened in private window all things that GoDaddy support told me to do.