Wow! I would have thought an organization as sophisticated as Xfinity would make whitelisting domains an option in their email platform. Everytime I'm expecting an email from this particular associate of mine, I have to log in to Xfinity and mark the email as "not spam" (not convenient). I'd like to just receive it in my email client normally like all my other emails. Am I missing something? Is there actually a way to do that?
Comcast should provide a way users can whitelist a sender so their mail would not be considered spam, but they don't. And unfortunately, the "Not Spam" function takes a lot of clicking on a lot of messages to perhaps stop future messages from being filtered.
If @ComcastAntiSpam or another employee doesn't respond here in the Forums, Comcast Security Assurance might be able to help if it's just one or two addresses. You can reach them at 1-888-565-4329 (from https://internetsecurity.xfinity.com/help/report-abuse/). Note that this is NOT one of the general customer service numbers. The first-line reps there are sometimes not very helpful, so you may need to be persistent and keep at them until you get a satisfactory answer.
Without Comcast's help or if this is happening with a large number of senders and "Not Spam" doesn't work, the only thing you can do to prevent messages from going to the spam folder is to turn spam filtering off completely so that everything they deliver is placed in the Inbox.
I have found the Comcast spam filter to be useless. They put emails I sent to MYSELF in the spam folder. I ended up cancelling my Google Alerts on 10 or so different subjects. Even though all came from the exact same address, on a daily basis some wouldn't arrive in my mail client. Checking Xfinity, I would find them in spam. It was bizarre. One day one subject would be there, next day in spam.
I ended up with 3rd level support, and NOTHING worked. No rules, no deleting and creating new alerts. One thing the daily checking showed me was how many other legimate emails were erroneously marked as spam. I have turned the filter off and will relty on Thunderbird and self designating from now on. Certainly couldn't do worse.
That seems like a very savvy solution. My Xfinity spam folder doesn't really fill up fast anyway, so I will turn off Xfinity spam filtering and rely on Thunderbird for that.