Email IMAP problem since upgrading.
Cannot say if this is related to the new firmware or not, but it happened about 1 day after upgrading to it, and there are no other reasons I can determine so far. I have been using Bluehost for my hosting and email on my named domain. I have 8 different email accounts on that domain, all configured as IMAP via secure access. I use Outlook on 2 PCs and have 2 Android devices that all access it. I've had zero problems until right after upgrading the router firmware. A day or so after doing so, I could no longer log into my primary IMAP email account because of a [Too many IP addresses [20] accessing account] error; webmail worked fine, so the account was still up. Error occurring on all of my devices with email clients, and could not resolve through any settings changes. No errors or blocks reported by Norton. Also, confined to my primary email account, not all of the email accounts on my domain; but then I poll my primary account more often than any other.
I have configured the router to save the system log to my main PC, using its IP address, but either it does not do so or I just can't find it, so I can't say if the router is reporting any errors or bounce-backs. A week after filing a trouble ticket, Bluehost responded by saying that I had a bunch of blacklisted IP addresses now, and that it looked like I may have been sending out large numbers of emails or spam, but I have not and nobody has sent me an email saying they were getting spam from me. Unfortunately, I cannot access the logs on Bluehost to see what IP addresses they are referring to, and they've not yet responded.
I fully realize that there are still many possible reasons for this problem suddenly appearing, including a hosting service that has gone to,,,, well, you know where. I only report it here because it began a day after upgrading the firmware. Don't know how long it will take to resolve it, so I can't say much more at the moment.