数据库版本oracle 11g，操作系统redhat6.8。浏览器中无法正常打开，提示“The database is down. Please specify the host credentials to access database restart and diagnostics tools.”
在服务器中，查看agent状态如下：
elcndc5pwxt01</home/oracle>$emctl status agent
Oracle Enterprise Manager 11g Database Control Release 11.2.0.4.0
Copyright © 1996, 2013 Oracle Corporation. All rights reserved.

Agent Version : 10.2.0.4.5
OMS Version : 10.2.0.4.5
Protocol Version : 10.2.0.4.5
Agent Home : /oracle/app/product/11.2.0/db_1/elcndc5pwxt01_juchang
Agent binaries : /oracle/app/product/11.2.0/db_1
Agent Process ID : 107994
Parent Process ID : 107947
Agent URL : https://elcndc5pwxt01:3938/emd/main
Repository URL : https://elcndc5pwxt01:1158/em/upload/
Started at : 2019-10-15 13:29:16
Started by user : oracle
Last Reload : 2019-10-15 13:35:19
Last successful upload : (none)
Last attempted upload : (none)
Total Megabytes of XML files uploaded so far : 0.00
Number of XML files pending upload : 673
Size of XML files pending upload(MB) : 45.94
Available disk space on upload filesystem : 87.77%
Data channel upload directory : /oracle/app/product/11.2.0/db_1/elcndc5pwxt01_juchang/sysman/recv
Collection Status : Disabled by Upload Manager
Last attempted heartbeat to OMS : 2019-12-17 11:02:46
Last successful heartbeat to OMS : unknown

Agent is Running and Ready

在linux集群环境下，此问题如何解决？除emca -config dbcontrol db -repos recreate外，是否有其他办法，谢谢