Alfresco升级后登录失败，抛出Connection refused异常求助

刚完成Alfresco系统升级，结果尝试登录新版本时直接抛出了连接拒绝的异常，折腾了半天没找到根源，特来求助各位技术大神！

异常栈信息如下：

java.net.ConnectException: Connection refused
    at java.net.PlainSocketImpl.socketConnect(Native Method)
    at java.net.PlainSocketImpl.doConnect(PlainSocketImpl.java:333)
    at java.net.PlainSocketImpl.connectToAddress(PlainSocketImpl.java:195)
    at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:182)
    at java.net.SocksSocketImpl.connect(SocksSocketImpl.java:366)
    at java.net.Socket.connect(Socket.java:525)
    at com.sun.net.ssl.internal.ssl.SSLSocketImpl.connect(SSLSocketImpl.java:550)
    at com.sun.net.ssl.internal.ssl.SSLSocketImpl.<init>(SSLSocketImpl.java:394)
    at com.sun.net.ssl.internal.ssl.SSLSocketFactoryImpl.createSocket(SSLSocketFactoryImpl.java:123)
    at org.alfresco.encryption.ssl.AuthSSLProtocolSocketFactory.createSocket(AuthSSLProtocolSocketFactory.java:168)
    at org.apache.commons.httpclient.HttpConnection.open(HttpConnection.java:707)
    at org.apache.commons.httpclient.MultiThreadedHttpConnectionManager$HttpConnectionAdapter.open(MultiThreadedHttpConnectionManager.java:1361)
    at org.apache.commons.httpclient.HttpMethodDirector.executeWithRetry(HttpMethodDirector.java:387)
    at org.apache.commons.httpclient.HttpMethodDirector.executeMethod(HttpMethodDirector.java:171)
    at org.apache.commons.httpclient.HttpClient.executeMethod(HttpClient.java:397)
    at org.apache.commons.httpclient.HttpClient.executeMethod(HttpClient.java:323)
    at org.alfresco.httpclient.AbstractHttpClient.executeMethod(AbstractHttpClient.java:133)
    at org.alfresco.httpclient.AbstractHttpClient.sendRemoteRequest(AbstractHttpClient.java:85)
    at org.alfresco.httpclient.HttpClientFactory$HttpsClient.sendRequest(HttpClientFactory.java:307)
    at org.alfresco.solr.client.SOLRAPIClient.getModelsDiff(SOLRAPIClient.java:982)
    at org.alfresco.solr.tracker.CoreTracker.trackModels(CoreTracker.java:1405)
    at org.alfresco.solr.tracker.CoreTracker.trackRepository(CoreTracker.java:1127)
    at org.alfresco.solr.tracker.CoreTracker.updateIndex(CoreTracker.java:481)
    at org.alfresco.solr.tracker.CoreTrackerJob.execute(CoreTrackerJob.java:45)
    at org.quartz.core.JobRunShell.run(JobRunShell.java:216)
    at org.quartz.simpl.SimpleThreadPool$WorkerThread.run(SimpleThreadPool.java:549)

从栈信息看是Solr客户端连接时出了问题，但我对这块的配置细节不太熟悉，有没有大佬能指点下可能的排查方向或者解决办法？万分感谢！

内容的提问来源于stack exchange，提问作者abbr