Marking as Not Spam giving error messages

Non-spam messages frequently appear in myemail spam folder.  When I click the thumbs up icon to move them to my inbox, I often get server error messages, and the non-spam messages remain in the spam folder.  I should be able to check the box beside all non-spam messages, click the thumbs up to mark them as not spam, and have all of them moved into the inbox immediately.  Instead, it commonly requires checking and marking them not spam multiple times before they are moved.

Marking messages as not spam seems to have no effect on the filtering, as messages from the same senders frequently appear again in the spam folder.  There should be a way for users to white-list legitimate senders.