Outlook has stopped connecting to email servers, except over a VPN

[CampbellM]

I have an O2 5G SIM in my router.  About a day or so ago I was getting the following message from Outlook when connecting to a number of different email servers:

"Task ’[my email account] - Receiving’ reported error (0x800CCC1A) : ’Your server does not support the connection encryption type you have specified. Try changing the encryption method. Contact your email server administrator or Internet service provider (ISP) for additional assistance.’"

I have a number of different email accounts with a number of different companies and this started happening with two or three of them simultaneously.  And I have discovered that if I connect my PC via a VPN, everything works properly.  For both these reasons I think that the problem is somewhere in O2's network rather than at my end or the email server end.

I have tried ringing O2 Customer Service three times, but they have been unable to help.

Has anyone seen the same issue or have a solution?

[Enlli]

One for @madasaf1sh 

[CampbellM]

What personal information I have posted?

[Enlli]

None.

It's a permanent footer. You will be surprised what information people give away on here

[CampbellM]

Oh, OK.

[madasaf1sh]

@Enlli thanks for the tag.... 

@CampbellM 

What protocol are you using to connect to the Mail Server and is this sending or receiving email..  as this is usually a port been blocked. 

[CampbellM]

I'm using POP3 and SMTP over SSL/TLS on port 995 incoming and 465 outgoing.  This is the same for all three servers which are hosted by different companies.  This has worked very well since I installed the mobile broadband router nearly a year ago and for many years before that on an ordinary router.  Then all of a sudden it stopped working a few days ago (not all of the time: it would work occasionally).  But if I connect over a VPN everything is fine.

[JimboDee]

I too have my o2 sim in a 5g router and can access most websites without issue, however outlook.com just times out like it is blocked by o2 network for some reason.

If I switch my network connection to my land line broadband I can access outlook.com fine, it just seems anoying that the default is for o2 network to block outlook.com.

[Enlli]

@JimboDee Working in Liverpool on 5G