Mail can't verify the identity of the server 'imap.plus.net"

[#1]

Hello everyone, thank you all for reaching out to us and I'm sorry to hear of the issues you are facing.

We have been made aware of an issue whereby users are being presented with an error that states "Mail can't verify the identity of the server mail.plus.com. This is currently under investigation and I would like to get more examples so that it can be thoroughly investigated, can I ask to private message me with the account details, the screenshot of the error and what email client you are using (Outlook, Apple mail, Gmail, etc). 

I will update this thread once we and incident raised and have a fix to the issue. 

Our apologies for any inconvenience this is causing. 

[#2]

on my Android 14 tablet and Android 15 phone I have

Digicert TLS ECC P384 Root G5 and Digicert TLS RSA 4096 Root G5

[#3]

So as a hypothesis this will impact any Android devices of version 13 and below.

As further data points I have:
Fire Tablet on Fire OS 8.3.3.3 ( Derived from Android 11)
Same list of certs as my Android 13 phone above (up to G4 but no G5)
Fire Tablet on Fire OS 7.3.3.1 ( Derived from Android 9)
Same list of certs as my Android 13 phone above (up to G4 but no G5)

K9-email is refusing to send on either of those.

[#4]

@Tina11192 

can I ask to private message me with the account details, the screenshot of the error and what email client you are using (Outlook, Apple mail, Gmail, etc).

I think you will also need the OS & version information

[#5]

Having accepted the certificate as trusted I cannot reproduce the issue.

[#6]

My certificate says it expires 10/8/2026 which in the UK was last night. Could it be that my iPhone (iOS 15.8.4, Apple Mail) or Plusnet mail thinks it is 2026? I can send out but not receive incoming messages.

[#7]

@Jane470

While clock differences certainly do cause issues with certificates and encryption I think what's happening here is that today the older certificate has been withdrawn and replaced with the newer one, the date overlap between the two likely just allowed for some flexibility of when the change happened.

[#8]

What Trust Store Version is on your phone @Jane470 ?

[#9]

Version 3, I think. Having trouble finding it again I’m afraid.

[#10]

I don't know where the Trust store version is on IOS15 is, @Jane470 , but on IOS18 it is under General>About>Certificate trust settings, and is a 10 numeric character string - in my case 2025031200. 

[#11]

Version: 1005.

[#12]

Ah, the current version is 1006. I wonder if IOS15 has fallen off the support platform?

[#13]

Sorry, I meant to say 2025031200 same as you.

[#14]

Sorry, start again. It should be 2022031500 version 1005. I’m getting tired.

[#15]

OK,not a problem, but it is strange you are on Trust Asset Version 1005, mine is 1006, on both IOS18.6 (phone) and iPadOS18.6.

EDIT: That suggests IOS15 is no longer supported, hence your 'issue'.