Problems setting up email address with my new Windows 10 Outlook

[#1]

New machine with Windows 10 and trying to setup my email account in Windows Outlook.   

Getting message: "Untrusted certificate".  The certificate from mail.bainhouse.co.uk.993.1 is invalid.  This might indicate and attempt to trick you or steal your info.   We don't recommend that you connect to this server.   Do you want to continue anyway?"

I have set this up in my old Outlook Express [my bainhouse.co.uk is via my Plusnet account] without any problems.

Can anyone please help.

I tried going via Thunderbird emailing and everything seemed fine there, but I really dont want to the Thunderbird programme unless I have to.

[#2]

If this mailbox is hosted on Plusnet servers, then the server names should be within plus.net which is the domain name for which the security certificates were issued.

I am surprised that smtp.yourdomain resolves if on Plusnet.

[#3]

Thank you Townman.  My mailboxes are hosted by Plusnet

Setup with Thunderbird without problems.   My mailboxes are hosted by Plusnet

Except it shows my bainhouse.co.uk [relay.plus.net] SMTP port as 587             and not port 25

and my default server name as bainhouse@plusdsl.net - relay-plus.net

and NOT the one I entered as bainhouse - relay.plus.net

Before investigating further will delete my Outlook account and will try again this time using the Thunderbird settings to see if that works.

Will let you know what happens.

[#4]

Problem solved at last!   I noticed that Thunderbird used IMAP and not POP3.   Put in these settings and it worked!

Thank you for replying to my problem.

[#5]

@bainhouse 

Whilst I'm please that you seem to have this working, this is not a solution to the problem you reported.

"Untrusted certificate".  The certificate from mail.bainhouse.co.uk.993.1 is invalid.

Port 993 is IMAP over SSL

By convention, mail. is the POP3 server, which should be addressed on port 995 for SSL - that said imap.plus.net resolves to the same group of servers as mail.plus.net

I am astonished to find that mail.yourdomain.co.uk is actually in the DNS and is a resolvable address, on checking I have found that imap. smtp. and relay. are not resolvable.

The issue here relates to the specification of mail servers using your own domain name, which does not match the server details contained in the security certificate.  The certificate refers to *.plus.net server names.

The issue here is that Outlook (and you have not specified the version of outlook) tries to guess the settings, unless you use the MANUAL configuration settings.  Left to its own devices, Outlook will...

• Take the email address you@yourdomain.co.uk
• Configure the inbound server as mail.yourdomain.co.uk (or imap.yourdomain.co.uk or pop3.yourdomain.co.uk)
• Configure the outbound server as smtp.yourdomain.co.uk

The correct servers are...

• imap.plus.net (for IMAP)
• mail.plus.net (for POP3)
• relay.plus.com (for SMTP)

Those are the server names identified in the SSL security certificates.  Therefore the attempt to use SSL with .yourdomain.co.uk will give rise to the "Untrusted Certificate" error you referenced.

Except it shows my bainhouse.co.uk [relay.plus.net] SMTP port as 587             and not port 25

Well port 25 is NOT the correct port for email CLIENT message submission.  Port 25 is the port for MX to MX message rely but is often used inappropriately.  Many networks will inhibit access to 'off network' SMTP servers if connection is attempted on port 25.  Message submission should always be done on port 587.

What is much more likely to have been an issue here is the selection of the SSL mode on on port 587 - it should be STARTTLS (not SSL/TLS).

As an aside some environments still support the use of the deprecated port 465 for SMTP SSL connectivity, which did support SSL auto configuration.

[#6]

The fact that...

• mail.yourdomain.co.uk is in the DNS
• smtp.yourdomain.co.uk is NOT in the DNS

... is not helpful where an email client makes ham-fisted presumptions about what are the correct email servers for youremail@yourdomain.co.uk - setting the SSL certificate issues aside, I can see this leading to inbound working OK whilst outbound fails totally.

Superuser citation

This topic has been cited by one of the Superusers; the purpose of which is to provide a note for information which might help to focus continued discussion (but might not result in a staff response).

[#7]

Many thanks again Townman for your invaluable information.  I do want to get this right, so will delete the account again and retry. 

I am over 70 and just bought this new machine [my laptop died on me] and not used to the new Microsoft 365 Personal "Outlook" email program yet [was a dab hand at setting up my old MSOffice 13 outlook but this one is driving me mad!!!.   I will seriously take on board, absorb your info and your advice and persevere until I get it setup properly.  

Many many thanks again

[#8]

@bainhouse I always use the Mail applet in the Control Panel when setting up Outlook, it gives full control over the settings and doesn't try to guess!

[#9]

@bainhouse 

You ought to be able to sort this when setting up, by choosing the "Set up server manually".

Unfortunately the advance settings option on the account properties no longer allows you to change the settings.  Following @Browni 's advice to use the control panel email applet will allow you to edit the settings on the current account's configuration.

You can also get to the old set up controls from within Outlook (well you can on OL 2016) via the Send & Receive settings...

Send & Receive tab -> Send & Received groups drop-down -> Define Send & Receive Groups (at the bottom)

All Accounts -> Edit

Select the account on the left

Click "Account Properties" on the right ... gives you full access to the old way of doing things.

[#10]

UREKA!!!!   following your advice, set incoming as mail.plus.net [port 110] and outgoing as relay.plus.net with port settings 587 and it has worked.   thank you so much Townman.   Must go and write it down in case I need  it for next time [hopefully not though]

[#11]

Glad that the advice helped you to fix the issue.  (I think the mods might have removed the previous "this fixed my problem" marker.)