Your mail server certificate is invalid error

My case with the "Your Mail Server Certificate is Invalid" error:

New Pixel 2 XL, Verizon carrier, Android 9 (Pie), Outlook mail app (down loaded from Google Play),  while attempting to add a networksolutionsemail.com account.

Here's what I found by pushing every combination of buttons in Outlook for the last several hours (and that only after most of the day fruitlessly Google searching for a solution)

From within the Outlook mail app:

Select Settings

Select Add Account

Select Add an Email

Enter your personal email address and Select Continue

When the screen returns with the Password field, tap the Help "?" (Are you kidding me!? Why the heck hide it behind the "?') where then and only then will a pop up appear to change the Account Provider.

Once Change Provider is selected then the  screen displays the Microsoft, Google, and Other account types incuding IMAP. When you select IMAP then it's back to the account setup screen to enter your password, your name, and name for the account.

However and Moreover, now when selecting Advanced it will display the Incoming and Outgoing IMAP server fields, of which my email account connected just fine when I left them blank.

As a foot note I had also contacted Outlook Support (found them behind the "?"as would be expected) about POP3.

"Thanks for reaching out and I am more than happy to provide information in regards to POP/POP3 accounts. Currently, we do not support POP or POP3 accounts. It is something we may consider adding in the future.

However, POP and POP3 have many limitations, such as the amount of time received mail remains on the server before being deleted and the ability to retrieve sent mail or sync changes in you mailbox on multiple devices.

I appreciate your time and I hope you are having a great day so far!:)"

Signed by my new friend Bob S- Outlook Mobile Support - Android Support / iOS Support (CSS)

Hope this helps.

Just to add a bit of background, Outlook app appears to be running all the time along with exchange, although the latter is probably associated with Live.com accounts too.

Basically, it's not working efficiently and is probably using a fair bit of battery in doing so.

Hello all,

I have just purchased a new huawei p smart running Android 8.00.

Spent some time trying to add my work email Outlook 365 but it returns the following error,

"Couldn't establish the connection to the server due to untrusted or invalid certificate"

This is with both Gmail and the built in email app, live.com account works fine with push email and notifications, tried Outlook app which does work in part, or at least it doesn't pop up with the certificate error. 

I would stick with this but the push functionality is missing along with notifications, you have to tap the app header or scroll down for it to sync, not ideal but it does work - if possible would like to use in-built app.

I spoke to hand set support along with my carrier, between u we tried just about everything although my carrier mentioned problems with Outlook previously but nothing recent, that said Oreo was only now being pushed out to their user base.

Thanks

Well, no such problem on Apple, cannot speak for Android, as I do not have Android.

The problem some off us had, was to do with the security that Microsoft had changed and updated and TalkTalk, the email provider had not updated, needed to be sorted, which now is, so may need to take it up with your email provider.

I AM referring to TalkTalk, and the original question posted by MarthaMerza specifically referred to Outlook for Android.

I had exactly the same issue - however, the gist of what I was saying is that even though the issue has been resolved (almost certainly not by Microsoft, although their actions initiated the problem) I still would not go back to using Outlook for Android for my TalkTalk email because it has so many other fundamental issues. Basically bug ridden.

Having said that, TalkTalk have proven themselves repeatedly to not be the "sharpest tools in the box" when it comes to security. For years they blithely ignored feedback about why their portal login page didn't even use HTTPS - until the crap hit the fan and they had that very large data breach.

Well, no such problem on Apple, cannot speak for Android, as I do not have Android.

The problem some off us had, was to do with the security that Microsoft had changed and updated and TalkTalk, the email provider had not updated, needed to be sorted, which now is, so may need to take it up with your email provider.