Comment 5 for bug 1866974

I've recently begun using `evolution-ews` from the Ubuntu 19.10 repository and it's been working brilliantly. I've now attempted to do the same on a fresh Ubuntu 20.04 beta install and can no longer use the plugin to fetch my emails, as I get a TLS/SSL error.

I'm using it on an NHS email account with the server URL as

`https://mail.nhs.net/ews/exchange.asmx`

but when I add my email account I get an error message

```
SSL/TLS certificate for "mail.nhs.net" is not trusted. Do you wish to accept it?
```

The certificate is for *.nhs.net so should be valid, I also get a reported error "Error perfroming TLS handshake. The Diffie-Hellman prime sent by the server is not acceptable (not long enough)

If I try to `Accept Permanently` the pop up box continues to reappear.

```
*.nhs.net
Identity: *.nhs.net
Verified by: GlobalSign RSA OV SSL CA 2018
Expires: 14/03/21
```

## On Ubuntu 19.10 (Working)
```
neil@thinkpad:~$ apt search evolution
Sorting... Done
Full Text Search... Done
evolution/eoan,now 3.34.1-2 amd64 [installed]
  groupware suite with mail client and organizer

neil@thinkpad:~$ apt search evolution-ews
Sorting... Done
Full Text Search... Done
evolution-ews/eoan,now 3.34.1-1 amd64 [installed]
  Exchange Web Services integration for Evolution
```

## On Ubuntu 20.04 (Error)
```
neil@thinkpad:~$ apt search evolution
Sorting... Done
Full Text Search... Done
evolution/focal,now 3.36.1-1 amd64 [installed]
  groupware suite with mail client and organizer

neil@thinkpad:~$ apt search evolution-ews
Sorting... Done
Full Text Search... Done
evolution-ews/focal,now 3.36.1-1 amd64 [installed]
  Exchange Web Services integration for Evolution
```