Users who were using eM Client configured with IMAP & CardDAV/CalDAV on previous versions of SmarterMail without issue had CardDAV/CalDAV go offline in eM Client after the upgrade from Build 8451 to 8496.
Their eM Client diagnostic log has the following:
11:55:56.452|00B| Request:
12:00:56.403|018| Method: PROPFIND, RequestUri: 'https://smartermail.scarabmedia.com/';, Version: 1.1, Content: System.Net.Http.StreamContent, Headers:
12:00:56.403|018| {
12:00:56.403|018| Accept: text/xml
12:00:56.403|018| Brief: t
12:00:56.403|018| Depth: 1
12:00:56.403|018| User-Agent: eMClient/9.2.1577.0
12:00:56.403|018| Content-Type: text/xml; charset=utf-8
12:00:56.404|018| }
12:00:56.404|018| <?xml version="1.0" encoding="utf-8"?><D:propfind xmlns:D="DAV:"><D:prop><D:getetag /><D:displayname /><D:resourcetype /><D:sync-token /><supported-calendar-component-set xmlns="urn:ietf:params:xml:ns:caldav" /><supported-address-data xmlns="urn:ietf:params:xml:ns:carddav" /><xmpp-uri xmlns="http://calendarserver.org/ns/"; /><calendar-color xmlns="http://apple.com/ns/ical/"; /><D:supported-report-set /></D:prop></D:propfind>
12:00:56.404|018|
12:00:56.404|018| Response:
12:00:56.526|03D| StatusCode: 405, ReasonPhrase: 'Method Not Allowed', Version: 1.1, Content: System.Net.Http.HttpConnectionResponseContent, Headers:
12:00:56.526|03D| {
12:00:56.527|03D| Alt-Svc: h3=":443"; ma=86400; persist=1
12:00:56.527|03D| Date: Wed, 12 Apr 2023 19:00:56 GMT
12:00:56.527|03D| Allow: GET, HEAD, OPTIONS, TRACE
12:00:56.527|03D| Content-Type: text/html
12:00:56.527|03D| Content-Length: 1293
12:00:56.527|03D| }
12:00:56.527|03D| <!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Strict//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-strict.dtd">;
12:00:56.527|03D| <html xmlns="http://www.w3.org/1999/xhtml">;
12:00:56.527|03D| <head>
12:00:56.527|03D| <meta http-equiv="Content-Type" content="text/html; charset=iso-8859-1"/>
12:00:56.527|03D| <title>405 - HTTP verb used to access this page is not allowed.</title>
12:00:56.527|03D| <style type="text/css">
12:00:56.527|03D| <!--
12:00:56.527|03D| body{margin:0;font-size:.7em;font-family:Verdana, Arial, Helvetica, sans-serif;background:#EEEEEE;}
12:00:56.527|03D| fieldset{padding:0 15px 10px 15px;}
12:00:56.527|03D| h1{font-size:2.4em;margin:0;color:#FFF;}
12:00:56.527|03D| h2{font-size:1.7em;margin:0;color:#CC0000;}
12:00:56.527|03D| h3{font-size:1.2em;margin:10px 0 0 0;color:#000000;}
12:00:56.527|03D| #header{width:96%;margin:0 0 0 0;padding:6px 2% 6px 2%;font-family:"trebuchet MS", Verdana, sans-serif;color:#FFF;
12:00:56.527|03D| background-color:#555555;}
12:00:56.527|03D| #content{margin:0 0 0 2%;position:relative;}
12:00:56.528|03D| .content-container{background:#FFF;width:96%;margin-top:8px;padding:10px;position:relative;}
12:00:56.528|03D| -->
12:00:56.528|03D| </style>
12:00:56.528|03D| </head>
12:00:56.528|03D| <body>
12:00:56.528|03D| <div id="header"><h1>Server Error</h1></div>
12:00:56.528|03D| <div id="content">
12:00:56.528|03D| <div class="content-container"><fieldset>
12:00:56.528|03D| <h2>405 - HTTP verb used to access this page is not allowed.</h2>
12:00:56.528|03D| <h3>The page you are looking for cannot be displayed because an invalid method (HTTP verb) was used to attempt access.</h3>
12:00:56.528|03D| </fieldset></div>
12:00:56.528|03D| </div>
12:00:56.528|03D| </body>
12:00:56.528|03D| </html>
12:00:56.528|03D|
12:00:56.528|03D|
12:00:56.528|03D| AccountBase.ChangeOnlineState : State changed to OFFLINE due ConfigurationChangedAs a work-around we have them deleting the IMAP and CardDAV/CalDAV accounts in eM Client and re-adding the account, letting eM Client autodetect and autoconfigure for EWS.
A possible cause: We noticed that the SmarterMail server has WebDAV installed as a feature in IIS (probably has been for years). We have removed WebDAV and are pending a restart after-hours to determine if this resolves the PROPFIND rsp "405 method not allowed" error with Build 8496. Will update tomorrow if this resolves it.