some emails seem to be blocked

[#1]

I am using Thunderbird  and emails from friends seem to be blocked. They never appear in my inbox. Also emails from Readers Digest have suddenly stopped coming. These are the codes for the £5000 draw so it really annoying. I have checked not only on Firefox  Thunderbird but also Plusnet webmail and  Windows live Mail. Nothing is there either. All the ones I know that are blocked are in my contacts register. I am on Windows 8.1 and have never had this trouble before neither have I fiddled about with the settings (I wouldn't know how to).

[#2]

I've just sent a test email to your Plusnet email address and it arrived almost immediately. There are also plenty of other messages visible on the server which you should be able to see when logging into Webmail. Does this problem only affect certain senders? If so, we'd need some more details around who it is that can't email you, what address they're sending from and what happens at their side when they try? (probably best to send that detail in a private message or a support ticket as these forums are publicly accessible).