1. Is the phone set up to use imap or pop?
2. Is the account in Thunderbird set up as imap or pop ?
3. If you logon to your webmail account via a browser do you see all the emails in the Junk folder ?

Thank you for taking the trouble to reply. I don't know about the setting up of the devices and I'm not sure how to find out. I have discovered more about the problem though. It seems to be the case that there are two different problems which have collided to produce a bigger issue.

1. My internet is provided by BT and my native email address is @btinternet.com. However I have a personalised domain name which is parked with namesco, and I use this as a personalised email address. The email for the domain is set up to forward everything to the @btinternet.com address. Mostly this works fine and has been more or less working fine for many years. But.

2. What I did not realise is that BT itself flags emails it doesn't like as spam. These emails should, I believe, go straight to the recipient's spam folder, but this is not happening in Thunderbird. Instead of going to a spam folder they simply vanish. This has always been the case but I didn't realise until yesterday. This seems to be the crux of my problem with Thunderbird. I'm not receving emails that BT has marked as spam.

3. I have the BT Mail app on my phone. This was only installed about six months ago and I haven't paid a lot of attention to it. However, I discovered yesterday that the emails BT has marked as spam ARE going to the spam folder in that. (This is regardless of whether they were originally sent to @btinternet.com directly, or forwarded from namesco.)

I trawled through that spam box, which only holds a month's emails, and found a number of genuine emails - including the one advising me about your reply. I marked these as not-spam and white-listed the domains, and at that point they all appeared in my Thunderbird inbox. As a work-round this is helpful, but I'd really like to fix it properly.

4. The crux of the problem, I now realise, is that BT has been flagging a lot of genuine emails as spam when they have been forwarded from namesco, but not flagging the same emails when they have come into @btinternet directly. The result of this was that it appeared that emails from certain accounts (mainly large companies like Amazon, inevitably) were vanishing when sent to my personalised address, but coming through correctly when sent directly to @btinternet.com. This is the half of the problem that I need to pursue with BT.

The issue with Thunderbird is that the emails BT seems to be trying to send straight to my spam folder are not being received by Thunderbird. I did try at one point to reset the parameters for the Thunderbird spam folders but it didn't make any difference. The advice I need is what to do to Thunderbird so that it gets the emails BT thinks are spam.

(Someone suggested that the emails were being deleted from the server when the phone received them, so that they weren't getting to Thunderbird, but this can't be the explanation. The BT Mail app has only been on my phone since December, and the issue has being going on for years, with accounts becoming affected one at a time, presumably as the BT servers took against them. It started to happen before I even possessed a smartphone.)

Thank you for any light you can shed on this.

Thank you for taking the trouble to reply. I don't know about the setting up of the devices and I'm not sure how to find out......

In Thunderbird

• In Account Settings
• Select 'Server Settings' for the account
• Top right it will say 'Server Type'

Does it say 'Pop Mail Server' or 'Imap Mail Server' ?

1. My internet is provided by BT and my native email address is @btinternet.com. However I have a personalised domain name which is parked with namesco, and I use this as a personalised email address. The email for the domain is set up to forward everything to the @btinternet.com address. Mostly this works fine and has been more or less working fine for many years. But. 2. What I did not realise is that BT itself flags emails it doesn't like as spam. These emails should, I believe, go straight to the recipient's spam folder, but this is not happening in Thunderbird. Instead of going to a spam folder they simply vanish. This has always been the case but I didn't realise until yesterday. This seems to be the crux of my problem with Thunderbird. I'm not receving emails that BT has marked as spam.

All servers have their own Spam Filters and if they think something is spam then they put it in the server 'Spam' folder. Thunderbird has no control over anything any server does with Spam or what it thinks is Spam. Only you can access the webmail account and instruct the server what the server must allow as good/not spam emails.

You can see what they put into the server 'Spam' folder if you logon to your webmail account via a browser OR if you are using an IMAP account because it synchronises with the server Spam folder.

3. I have the BT Mail app on my phone. This was only installed about six months ago and I haven't paid a lot of attention to it. However, I discovered yesterday that the emails BT has marked as spam ARE going to the spam folder in that. (This is regardless of whether they were originally sent to @btinternet.com directly, or forwarded from namesco.)

If you can see emails in the Spam folder in the mail app then you are using an IMAP which synchronises folders - basically a mirror image of what is on server.

I trawled through that spam box, which only holds a month's emails, and found a number of genuine emails - including the one advising me about your reply. I marked these as not-spam and white-listed the domains, and at that point they all appeared in my Thunderbird inbox. As a work-round this is helpful, but I'd really like to fix it properly.

AS far as the BT server spam filter is concerned, it's not a workaround. That is the action you need to do when it comes to instructing the server, so that emails are correctly put into the correct folder in the first place. This would be required where you use IMAP or POP. After all, even if you do use IMAP and see the SPAM folder, you do not want to keep having to move emails out of that folder.

When you stated those emails were 'good', they got put into the server 'Inbox' and therefore all emails could be downloaded to Thunderbird. This is begining to sound like you have a Pop account for the bt account in Thunderbird. It's impossible for a POP account to see anything in server folders because no POP account folder synchronises with any server folder. It can just access server Inbox and download whatever is in it. But if you check the Account Settings > Server SEttings then it will tell you what you have in Thunderbird.

4. The crux of the problem, I now realise, is that BT has been flagging a lot of genuine emails as spam when they have been forwarded from namesco, but not flagging the same emails when they have come into @btinternet directly. The result of this was that it appeared that emails from certain accounts (mainly large companies like Amazon, inevitably) were vanishing when sent to my personalised address, but coming through correctly when sent directly to @btinternet.com. This is the half of the problem that I need to pursue with BT. The issue with Thunderbird is that the emails BT seems to be trying to send straight to my spam folder are not being received by Thunderbird. I did try at one point to reset the parameters for the Thunderbird spam folders but it didn't make any difference. The advice I need is what to do to Thunderbird so that it gets the emails BT thinks are spam.

IF you have a POP account in Thunderbird then it will not be able to download emails that do not exist in the server 'Inbox'. If email is in SPAM then POP account is never going to download it until you put email into the 'Inbox' - you can do that via the phone BT Mail app - just mark as not spam or manually move to Inbox - then the folder will synchronise with server and move the email into Inbox or set up webmail server to not mark them as spam so they stay in Inbox in the first place.

(Someone suggested that the emails were being deleted from the server when the phone received them, so that they weren't getting to Thunderbird, but this can't be the explanation. The BT Mail app has only been on my phone since December, and the issue has being going on for years, with accounts becoming affected one at a time, presumably as the BT servers took against them. It started to happen before I even possessed a smartphone.) Thank you for any light you can shed on this.

If emails were in the server Inbox and on phone you had the BT Mail app set up as a pop account AND it accessed the server Inbox prior to the Thunderbird POP account, then yes it is possible that the first pop account deleted them off the server if you did have a setting to leave message on server...but that is not the case - you see them in the webmail server 'Spam' folder and you see them in the BT MAIL app Spam folder - so clearly they not are being deleted - server puts email in Spam and BT Mail App uses IMAP so it can see what is in SPAM. It's likely Thunderbird BT account is not IMAP, but you need to check and let me know what it says.

Sorry not to have replied sooner. I was waiting for BT to get back to me to explain why their system is throwing a ton of emails that are not spam into a spam black hole. They finally got back to me today, as I'm packing to go on holiday, so I'm going to have to park it till I get back.

Thanks again and I'll probably be picking your brains again in a couple of weeks if you don't mind.