If you have a Pro License, please open a support ticket with eM Client. They will be able to comment further or offer some solution.
i have a pro license and i have contacted support already - and no there is no resolution. em client says it is swisscom’s fault, swisscom says it is em client’s fault.
this leaves users with a bluewin.ch mail account between a rock and a hard place! not a nice place to be.
Unfortunate. I don’t see eM Client Inc. budging on this; they certainly have not made any visible effort in the past to accommodate other incompatible servers, or maybe it is just not possible for them to do anything.
It seems that unless the provider can change something, there will be no resolution.
But re-reading this thread, it appears that you have already blamed the provider for this, and demonstrated that there is no issue with new accounts created with them. Does this not clearly show where the problem is?
maybe it would help if em client inc. made swisscom officially aware of the problem. i have tried, but as a single user you just get brushed off. em client should have a bigger gun than i have. 
Maybe suggest that to eM Client Inc.
But you would also think that if enough swisscom customers approached their provider, they would pay attention.
Actually, you would think that if just one customer approached them, they would pay attention.
yep - this you would think. but the reality is different and does not work like this. here the statement from em client support:
Although I understand your situation, our application isn’t malfunctioning and from the developer’s point of view there’s nothing to fix. The application is designed to use the authentication mechanism with the highest possible security level.
In this case, it’s CRAM-MD5 and for Bluewin to fix this they just need to remove this authentication method from the server capabilities, then eM Client will use PLAIN authentication on the SSL port automatically.
this is just another case which proofs the statement of “edv” in german.
“elektronische datenverarbeitung” would be “electronic data processing” in english - but is more often than not: “ende der vernunft” - “end of reason”.
Hello all,
We are aware of this Swisscom/Bluewin issue and we were trying to reach to the email provider for a fix.
The problem is, that the mail server is faultily reporting the Cram-MD5 authentication as a top-secure option - then eM Client insists on keeping this secured connection. In fact, the server doesn’t support Cram-MD5 authentication and eM Client because of security reason is not willing to step-down to another less secure authentication method (plain text). After that, the relation between eM Client and the server is cancelled.
We asked the provider several times to fix the autosetup so the mail server doesn’t report the Cram-MD5 authentication method and the relation can work from the beginning on another authentication method (SSL/plain-text). Unfortunately, we were unsuccessful and from the official Swisscom’s statement: “Somit unterstützt Swisscom CRAM-MD5 offenbar by design NICHT. Was bedeutet, dass Swisscom-Kunden den emClient nicht verwenden können. Wenn man bedenkt, dass Swisscom der grösste kommerzielle Mailanbieter in der Schweiz ist, sind das doch einige potenzielle emClient Kunden.” results the unwillingness to fix anything.
The only solution is that the Swisscom/Bluewin fixes their server settings so eM Client can start their proposed SSL authentication from the start of the relation (eM Client supports SSL). We believe that together with their plan to finally abandon Cram-MD5 on their servers it will happen asap. "MD5-Challenge-Response als Authentifizierungsmethode ist heute obsolete und wird von Swisscom Mitte 2019 eingestellt."
Thank you for your patience and we believe that you’ll be able to use eM Client with Swisscom/Bluewin again without issues.
Russel
So unlike one of my providers. When I began using eM Client with GMX, there were issues getting CalDAV to work, but just one or two emails from me and GMX and eM Client got together and resolved it. Now CalDAV works seamlessly when setting up a GMX account. There was no consideration that I was just one of a few eM Client users with them. They tried to resolve the situation regardless.
thanks russel
that at least shows clearly where the problem is - and we have a ray of hope that all will be well - sometimes in the future. 
I saw this notice after i was trying to reinstalling all on my em-client. Now i lost all my mails. Is there i chance to get them back? I have a bluewin.ch mail-adress?
only by uninstalling the programm you dont lose yor mails, you have to delete the folder inside the roaming path to delete everything.
what kind of account do you have - pop or imap?
That changed a few versions back Christopher. Now, during the uninstall, you are asked if you want to delete the database.
Unfortunately Gaby, if you are using POP3 and you either delete the account from eM Client, or you delete the database directory during the uninstall, you also permanently delete the messages. The only recourse will be to restore your most recent backup.
ame here, my compagny cant send email. useless product
Yes Jean-Pierre, I think we can now all agree that Swisscom/Bluewin is useless. Maybe after their upcoming reconfig, things will look better.
yes use live mail or thunderbird. webmail or inbox they all working well
well jean-pierre, sending emails has not been a problem, only receiving. if you have a sending problem then check the swisscom website and adjust your settings for sending email.
Or use any of 1000 other email providers all working well with eM Client. I know Christopher, you don’t approve of that comment. Hopefully the upcoming changes they are promising with removing the misconfigured CRAM-MD5 will result in a usable email provider, and this thread can finally be closed.
gary, christopher is not the only one not approving that comment. in most cases it is not just black or white. in general swisscom are offering a good product - but in this case not. at the same time: it took long for em client to come out with an official statement. info always helps to cool down the emotions.
no worries, i still like em client and keep on recommending it.
gary, christopher is not the only one not approving that comment. in most cases it is not just black or white. in general swisscom are offering a good product - but in this case not. at the same time: it took long for em client to come out with an official statement. info always helps to cool down the emotions.
no worries, i still like em client and keep on recommending it.