https does not work

I have some questions about how to get https://www.soapui.org/docs/soap-mocking/securing-mockservices-with-ssl/  to work:

1. Is it correct that the only thing I have to do on the client side is changing http to https? Or should I change the endpoint port number from 8088 to 8443 (the Mock Port on the SSL Settings tab in the SoapUI Preferences dialog) as well?
2. On the server side, should I leave port number as 8088 or change it to 8443?
3. Do I need to set up the Mock TrustStore, if I don't check requires client authentication?
4. Does it matter if the name of the cert matches the host name part of the url?

It works with http, but regardless of how I change the settings, I can't get the call to work with https. The error message is "Unrecognized SSL message, plaintext connection?" My SoapUI log tab contains:

Tue Jan 26 14:38:10 CET 2021:INFO:Started mockService [NumberConversionSoapBinding MockService] on port [8088] at path [/mockNumberConversionSoapBinding]
Tue Jan 26 14:38:19 CET 2021:DEBUG:Attempt 1 to execute request
Tue Jan 26 14:38:19 CET 2021:DEBUG:Sending request: POST /mockNumberConversionSoapBinding HTTP/1.1
Tue Jan 26 14:38:19 CET 2021:DEBUG:I/O error closing connection
javax.net.ssl.SSLException: Connection has been shutdown: javax.net.ssl.SSLException: Unrecognized SSL message, plaintext connection?
at sun.security.ssl.SSLSocketImpl.checkEOF(Unknown Source)
at sun.security.ssl.SSLSocketImpl.checkWrite(Unknown Source)
at sun.security.ssl.AppOutputStream.write(Unknown Source)
at org.apache.http.impl.io.AbstractSessionOutputBuffer.flushBuffer(AbstractSessionOutputBuffer.java:131)
at org.apache.http.impl.io.AbstractSessionOutputBuffer.flush(AbstractSessionOutputBuffer.java:138)
at org.apache.http.impl.conn.LoggingSessionOutputBuffer.flush(LoggingSessionOutputBuffer.java:95)
at org.apache.http.impl.AbstractHttpClientConnection.doFlush(AbstractHttpClientConnection.java:270)
at org.apache.http.impl.SocketHttpClientConnection.close(SocketHttpClientConnection.java:245)
at org.apache.http.impl.conn.DefaultClientConnection.close(DefaultClientConnection.java:164)
at org.apache.http.impl.conn.AbstractPooledConnAdapter.close(AbstractPooledConnAdapter.java:152)
at org.apache.http.protocol.HttpRequestExecutor.closeConnection(HttpRequestExecutor.java:142)
at org.apache.http.protocol.HttpRequestExecutor.execute(HttpRequestExecutor.java:129)
at org.apache.http.impl.client.DefaultRequestDirector.tryExecute(DefaultRequestDirector.java:633)
at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:454)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:820)
at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:754)
at com.eviware.soapui.impl.wsdl.support.http.HttpClientSupport$Helper.execute(HttpClientSupport.java:233)
at com.eviware.soapui.impl.wsdl.support.http.HttpClientSupport.execute(HttpClientSupport.java:323)
at com.eviware.soapui.impl.wsdl.submit.transports.http.HttpClientRequestTransport.submitRequest(HttpClientRequestTransport.java:301)
at com.eviware.soapui.impl.wsdl.submit.transports.http.HttpClientRequestTransport.sendRequest(HttpClientRequestTransport.java:231)
at com.eviware.soapui.impl.wsdl.WsdlSubmit.run(WsdlSubmit.java:119)
at java.util.concurrent.Executors$RunnableAdapter.call(Unknown Source)
at java.util.concurrent.FutureTask.run(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor.runWorker(Unknown Source)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(Unknown Source)
at java.lang.Thread.run(Unknown Source)
Caused by: javax.net.ssl.SSLException: Unrecognized SSL message, plaintext connection?
at sun.security.ssl.InputRecord.handleUnknownRecord(Unknown Source)
at sun.security.ssl.InputRecord.read(Unknown Source)
at sun.security.ssl.SSLSocketImpl.readRecord(Unknown Source)
at sun.security.ssl.SSLSocketImpl.performInitialHandshake(Unknown Source)
at sun.security.ssl.SSLSocketImpl.writeRecord(Unknown Source)
at sun.security.ssl.AppOutputStream.write(Unknown Source)
at org.apache.http.impl.io.AbstractSessionOutputBuffer.flushBuffer(AbstractSessionOutputBuffer.java:131)
at org.apache.http.impl.io.AbstractSessionOutputBuffer.flush(AbstractSessionOutputBuffer.java:138)
at org.apache.http.impl.conn.LoggingSessionOutputBuffer.flush(LoggingSessionOutputBuffer.java:95)
at org.apache.http.impl.io.ContentLengthOutputStream.flush(ContentLengthOutputStream.java:102)
at org.apache.http.entity.ByteArrayEntity.writeTo(ByteArrayEntity.java:69)
at org.apache.http.entity.HttpEntityWrapper.writeTo(HttpEntityWrapper.java:96)
at org.apache.http.impl.client.EntityEnclosingRequestWrapper$EntityWrapper.writeTo(EntityEnclosingRequestWrapper.java:108)
at org.apache.http.impl.entity.EntitySerializer.serialize(EntitySerializer.java:120)
at org.apache.http.impl.AbstractHttpClientConnection.sendRequestEntity(AbstractHttpClientConnection.java:263)
at org.apache.http.impl.conn.AbstractClientConnAdapter.sendRequestEntity(AbstractClientConnAdapter.java:227)
at org.apache.http.protocol.HttpRequestExecutor.doSendRequest(HttpRequestExecutor.java:255)
at com.eviware.soapui.impl.wsdl.support.http.HttpClientSupport$SoapUIHttpRequestExecutor.doSendRequest(HttpClientSupport.java:119)
at org.apache.http.protocol.HttpRequestExecutor.execute(HttpRequestExecutor.java:123)
... 14 more
Tue Jan 26 14:38:19 CET 2021:DEBUG:Closing the connection.
Tue Jan 26 14:38:19 CET 2021:DEBUG:Connection closed
Tue Jan 26 14:38:19 CET 2021:DEBUG:Connection shut down
Tue Jan 26 14:38:19 CET 2021:ERROR:Exception in request: javax.net.ssl.SSLException: Unrecognized SSL message, plaintext connection?
Tue Jan 26 14:38:19 CET 2021:ERROR:An error occurred [Unrecognized SSL message, plaintext connection?], see error log for details
Tue Jan 26 14:38:19 CET 2021:INFO:Error getting response for [NumberConversionSoapBinding.NumberToDollars:Request 1]; javax.net.ssl.SSLException: Unrecognized SSL message, plaintext connection?