auto Plugin update not possible

Hi,

I want to run some auto updates for plugins running on http://www.spectrumconsult.net. I get asked connection information, I enter the data > message wrong user/pass. Contact your host. WTF!? Works fine on Filezilla. there is an ( and @ in the password, could that be it?
Only other reason I can think of is explicit FTP over TLS required. I read all the threads on this forum and more, nothing helps, nothing works. Please HELP!