Legacy Cumulus 1 release 1.9.4 (build 1099) - 28 November 2014
(a patch is available for 1.9.4 build 1099 that extends the date range of drop-down menus to 2030)
Download the Software (Cumulus MX / Cumulus 1 and other related items) from the Wiki
2021-11-14 08:34:50.730 MapsOn: Start
2021-11-14 08:34:50.735 Information MapsOn: Adding Station: Sandhem/Trollhättan
2021-11-14 08:34:50.762 Information MapsOn: Must NOT send signature, has been done already : 14/11/21
2021-11-14 08:34:50.763 Information Fetch Map: Fetching the generated map
2021-11-14 08:34:50.763 GetUrlData Start: URL - https://meteo-wagenborgen.nl/maps.txt
2021-11-14 08:34:50.764 Information GetUrlData Calling GetAsync
2021-11-14 08:34:51.435 Error GetUrlData : Exception - The SSL connection could not be established, see inner exception.
2021-11-14 08:34:51.454 Error GetUrlData: Inner Exception: System.Security.Authentication.AuthenticationException: Authentication failed, see inner exception. ---> Mono.Btls.MonoBtlsException: Ssl error:1000007d:SSL routines:OPENSSL_internal:CERTIFICATE_VERIFY_FAILED
at ./external/boringssl/ssl/handshake_client.c:1132
at Mono.Btls.MonoBtlsContext.ProcessHandshake () [0x00064] in <a85c1a570f9a4f9f9c3d2cfa5504e34f>:0
at Mono.Net.Security.MobileAuthenticatedStream.ProcessHandshake (Mono.Net.Security.AsyncOperationStatus status, System.Boolean renegotiate) [0x00106] in <a85c1a570f9a4f9f9c3d2cfa5504e34f>:0
at (wrapper remoting-invoke-with-check) Mono.Net.Security.MobileAuthenticatedStream.ProcessHandshake(Mono.Net.Security.AsyncOperationStatus,bool)
at Mono.Net.Security.AsyncHandshakeRequest.Run (Mono.Net.Security.AsyncOperationStatus status) [0x00006] in <a85c1a570f9a4f9f9c3d2cfa5504e34f>:0
at Mono.Net.Security.AsyncProtocolRequest.ProcessOperation (System.Threading.CancellationToken cancellationToken) [0x0012a] in <a85c1a570f9a4f9f9c3d2cfa5504e34f>:0
--- End of inner exception stack trace ---
at Mono.Net.Security.MobileAuthenticatedStream.ProcessAuthentication (System.Boolean runSynchronously, Mono.Net.Security.MonoSslAuthenticationOptions options, System.Threading.CancellationToken cancellationToken) [0x00346] in <a85c1a570f9a4f9f9c3d2cfa5504e34f>:0
at System.Net.Http.ConnectHelper.EstablishSslConnectionAsyncCore (System.IO.Stream stream, System.Net.Security.SslClientAuthenticationOptions sslOptions, System.Threading.CancellationToken cancellationToken) [0x000d2] in <3588d5c507ec48a6b5d13a6d5ae64da2>:0
2021-11-14 08:34:51.455 Error Fetch Map from server: Fail... empty map.
2021-11-14 08:34:51.458 Information Timing of Map generation = 743 ms
For the sending of the site signature file and the subsequent fetch of the map use is made of simple https get and post calls. These make use of the certificates just like your browser does (because of the https). The renewal of the certificate has been described in the links which go with release 6.6.0. You apparently skipped the 6.6.0 upgrade but you do need to upgrade to OpenSSL 1.1.0 which is described in the release notes (just as is required for upload to Windy.com by CMX itself):
Upgrade to OpenSSL 1.1.0, see links in Release Notes for 6.6.0, especially the third link on the Windy issue has Mark point to a StackOverflow post which contains a fix for debian 8, that should also work for you)