Add to Whitelist and Add to Blacklist not working 8.53

[rfwilliams777]

I have seen since we've upgraded to 8.53 (yes, I know it has not been publicly released) that when (in webmail) if you right click and choose either of those options that an error pops up saying that the email address does not exist when in fact it does. It does not happen to all emails that you wish to do this as it does work from time to time but I have seen it often enough and other users have commented it as well.