cybercannon created the issue

i have entered a ftp address and downloaded files without a problem, but when i close down the cyberduck and reopen again and use the bookmark to access the ftp address a pop appears with the user name and i re enter the password but it then says failed. even though all the details have been double checked and are correct. If i then start again and enter alll the details from the start it works without any problems.

can you help
richard