getting error "CANNOT VERIFY SERVER IDENTITY"

And you never tried to fix the problem after updating? While occasionally there are problems after updating they can always be easily fixed. If you are on 13.6 there is a major security vulnerability with it, which is why Apple released 13.6.1 just a week later. If you don’t mind having your phone at risk then by all means don’t update it. However, 13.6 is new enough to have the latest certificate store, so updating won’t fix the server problem.

What troubleshooting have you done for the server problem? What is the server identify that is being rejected? The two most common causes of that error are either a subscription calendar that expired and you never removed from the phone, or an email account with an out of date certificate. Either problem can be easily fixed.

There is a much less likely problem if you are trying to access a non-ISP email account on, say a private server (think Hillary Clinton in 2016) and the server’s certificate has expired. But even that can be fixed.

So which do you want to try first?

I didn’t know if the photo was your phone or from the thread that you posted.

For the imap.gmail.com go to Settings/Passwords & Accounts, tap on the gmail account and delete it.

Then restart your phone—>Restart your iPhone - Apple Support. (The restart is important, because without it when you add it back it will use the old data from the account.) Then add your gmail account back by going back to Settings/Passwords & Accounts, tapping Add Account then gmail and filling out the form. As it’s an IMAP account it will resync your messages with the server.

For the CaptivePortal error, I assume you are using a Nokia public website or a public website hosted by Nokia. Open Settings/Wi-Fi, find the network that you were trying to access when you got that message, tap on the i next to it and then “forget this network”. The next time you try to connect it should work. But public networks change their certificates frequently, so you can’t stay connected continuously for more than a few days without disconnecting and reconnecting.

While checking, go to Settings/Passwords & Accounts, scroll down to Subscribed Calendars, and review the calendars there. If any look unusual tap on each and delete it. There are no default subscribed calendars, so any that appear you added. If you didn’t add any the space should be empty under Subscribed Calendars.

Finally, to leave no stone unturned, go to Settings/General. Scroll to the bottom and look just below VPN. If there is an entry for Profiles or Device Management (there may not be) tap on it and review the profile certificates, and delete any you don’t recall installing.

If you continue to have problems after these steps post back; we haven’t used all of the arrows in the quiver.

Well, if you aren’t going to take advice you might as well throw away the phone.

I have and members of my family have had iPhones since June 2007, and I have installed every update that has ever come out and none of them have ever been a PHONE KILLER!

If you want help with that error and you are finished with your rant say so and someone will try to help you resolve it.

You can start by saying what model phone, what version of iOS, and what the name of the server whose identity can’t be verified is.

Are you configured within an organization’s network, or a VPN into an organization’s network?

That.Captive Portal domain shown might be SSL interception being detected and thwarted;,some organizations implement that.

This is easier to track from a Mac or Windows or Linux system with network route tracing tools, though.

You’re somehow getting directed elsewhere, then; this if a certificate for that Nokia domain is being returned when requesting gmail. That’s a VPN or a DNS error or a routing error, or malicious networking shenanigans, or Google has a badly misconfigured host.

Do you have add-on anti-malware installed, or any add-on VPN client apps?