Gee, most of these sites require membership, including this one. The folks at rcsb seem to be OK guys as far as I know and aren't likely to "delete" you on a whim.
The problem is likely with YOUR computer settings. Check your firewall/spamblocker/phishing filter/etc settings. Is someone else using your computer and tinkering with settings? I sometimes have to re-LogIn, but that's painless.