[Evolution] evolution deleted IMAP account & Exchange calendar. Doesn't work anymore

["Daniel P." <aglasis gmail com>]

For months I have used Evolution with my work email (Exchange) and
calendar (with EWS) with no trouble at all (Setting it up was a hellish
nightmare though, FYI)

Now, I started evolution to find out that the email account and
associated calendar simply disappeared. There was no update, no change
in OS, no change at all in the system, software or hardware. Simply
shut it down one day, turn it on the next, and see that everything is
gone. No error, no warning, simply disappeared. Other accounts (non-
exchange) are still there, but not the exchange one. 

I tried to add it again, and it doesn't work. All settings are defined
(as they were originally) just to see that, for some settings, there
are "unknown errors" or "connection failed" errors permanently, and the
account is never set-up or even recognized. For others, the account is
not even added, this without a warning. It just won't do it. And when
it manages to add the account, it can't reach it.

Furthermore, it never asks to confirm the password for the exchange
server

How to fix this?