Mail not sending!

Your last reference was to Mailbird- it seems you've reverted to Mail.

The choice of pop3 or imap for receiving mail is up to you.. smtp is a different thing.

Suggest you try sending mail with Mailbird

I've been using the built in Mail client with W10 since it came out, initially it was awful, very buggy, but it is a lot better now.

As an A/B try sending via the webmail interface of whatever email addresses you have including your ISP if you use their email.

As already mentioned bulk sending is probably a spam issue at the SMTP end, it may vary according to who's SMTP you use.
You need to be careful with bulk sending otherwise you can end up on the blacklists like Spamhaus etc. and it isn't trivial getting off of them.

WRT to 'backups' it is easy to set up one webmail account to either POP3 or IMAP mirror to another (I use both, the POP3 is effectively an inbox archive).
I do it across ecosystems (MS/Google) to give me some cloud outage redundancy. No desktop client involvement at all.
Mail can be set to download everything but it doesn't have any proper offline backup like Outlook (.pst) or Thunderbird.

As long as you have some ISP redundancy (BB + Mobile tethering or two mobiles with tethering) then it isn't a major issue (for me anyway...).

Edit: This might help you fault trace if there are actual issues (beyond set up mistakes).https://serversmtp.com/smtp-error/

Web Mail = use a browser - just to test you can send an email to an address using your PC/ISP.

Google is great at questions like that:

People also ask

Is Mailbird really free?

Whereas the free version of Mailbird is limited to a single email account, Mailbird Pro lets you connect as many as you like. This is enormously useful, and the Unified Inbox lets you see the latest messages from all your accounts in a single convenient place.

Thunderbird is free- there are others.

The error message I keep receiving in the 'non-delivery' mail is the '550' variety...
Activating the link you sent I see that:

550 - usually defines a non-existent email address on the remote side.
Though it can be returned also by the recipient’s firewall (or when the incoming server is down), the great majority of errors 550 simply tell that the recipient email address doesn’t exist. You should contact the recipient otherwise and get the right address.

The mails were 'sent' to addresses I have had contact with for many years - double and triple checked to confirm they are correct and according to those I spoke to by land-line confirm their mail systems were/are fully functional and sent me 'test' mails instantly.

I had the same thing a few weeks ago when I sent a test email from my domain email to another rarely used address of mine, got the 550 bounceback even though I know the address is valid. On a hunch I whitelisted the to and from addresses at each end by putting them into contacts and everything was fine after that (5 minutes later).

As spam is such an issue the settings on many of the mail servers are quite sensitive at the moment, so it's probably best to whitelist your entire contacts directory to minimise issues, and make sure the other end whitelist your email addresses too, putting you into their address book if needs be.
If you can't fully whitelist in whatever desktop client you are currently using then do it via the webmail interface of each of your email addresses on a browser.

Edit: You can run multiple accounts in W10 Mail, but it doesn't have all the bells and whistles that say Thunderbird desktop client does (which is free also).
I don't need all the flexibility TB has but it is very good so worth learning if you have the inclination.

skyways1142 said:

Thanks for joining in the fun!

You say:
On a hunch I whitelisted the to and from addresses at each end by putting them into contacts and everything was fine after that (5 minutes later).

As spam is such an issue the settings on many of the mail servers are quite sensitive at the moment, so it's probably best to whitelist your entire contacts directory to minimise issues, and make sure the other end whitelist your email addresses too, putting you into their address book if needs be.

I have only attempted to send mail to addresses within my contacts list. So is there anything else to do to 'whiteleist' my contacts?
The silly part of this is the fact that incoming mails are fine ~~~ just not sending

If you can, let your contacts know they need to whitelist your address(es) by making them address book contacts ideally.
Obviously any contacts that are currently giving you the 550 bounceback will need to be contacted by means other than email, can you SMS or WhatsApp them?
Once you resolve it put something in your email signature to the effect that your address needs to be whitelisted via address book contacts or 'this is not spam' directives.

Another possibility is that the 550 is the result of whoever you are sending to, their email host may have had issues with your email provider previously, so it might be on a spam (or worse) blocking list that has had its filter level 'actions' changed to something more draconian.

These things do change, just because it was OK before doesn't mean it will remain that way.

I recently had a 'spammed' legitimate email from my bank (who are whitelisted) that got treated that way because the SMTP address had changed to a known (but legitimate) bulk mailer who flag up on some of the spam blacklists, and the reply address was changed to no-reply@mybank.co.uk.
I figured out it was legit via the SPF/DKIM and DMARC= pass headers, but I wouldn't be surprised if loads of people labeled it a phishing attempt and then wondered why their bank emails had stopped...

Edit: Another complication is that whitelisting is extending to actual machines (PC's, phones, tablets et al) for logged in services, to try and prevent hacking.
So maybe the fact that you are sending from your 'old' email from a 'new' W10 machine with a different IP/MAC address has triggered something at the receive end of the email chain as it differs from the previous logs they have for your email address(es), especially if you only ever used the one XP PC previously.

Try the very basic check as advised previously.

a. Log in to your tiscali account using a web browser (Edge, Firefox, Chrome...)

b. Try sending a test email.

If that succeeds, you know there's no need for that recipient to whitelist anything.

That's absolute basics.

c. Then return to your email client and try sending to the same email address.

Have you tried using a browser???

TalkTalk will NOT offer help with email clients. They WILL ask you to try using a browser.