Thanks for the logs
[2019-02-06T22:33:59.426Z] [WARN ] ice-extension-mngr-pool-1347 70002211 100161 200005 c.vmware.vise.vim.directory.extensions.DirectoryExtensionManager Detected an invalid signature for plugin: com.vmware.fallback.mixed:6.5.0 - com.vmware.vise.extensionfw.signing.PluginSignatureException: No META-INF/MANIFEST.MF entry found in the plugin zip file.
[2019-02-06T22:33:59.427Z] [INFO ] ice-extension-mngr-pool-1347 70002211 100161 200005 com.vmware.vise.extensionfw.impl.PackagesDeployer Could not resolve dependencies for plugins packages: [ com.vmware.fallback.mixed:6.5.0 requires: [ com.vmware.vsphere.client lessThan 6.0.2 ]; ];
[2019-02-06T22:33:59.428Z] [INFO ] plugin-validation1 com.vmware.vise.extensionfw.impl.OsgiUsageValidationService Started validation of OSGi bad practices.
[2019-02-06T22:33:59.428Z] [INFO ] plugin-validation1 com.vmware.vise.extensionfw.impl.OsgiUsageValidationService OSGi validation skipped for plugin package com.vmware.fallback.mixed:6.5.0. It is not deployed.
[2019-02-06T22:33:59.428Z] [INFO ] plugin-validation1 com.vmware.vise.extensionfw.impl.OsgiUsageValidationService Finished validation of OSGi bad practices.
[2019-02-06T22:33:59.430Z] [WARN ] ice-extension-mngr-pool-1348 70002211 100161 200005 c.vmware.vise.vim.directory.extensions.DirectoryExtensionManager Detected an invalid signature for plugin: com.vmware.vum.client:6.8.4.00000 - com.vmware.vise.extensionfw.signing.PluginSignatureException: The certificate common names (CN) [test] do not contain the expected one.
[2019-02-06T22:33:59.430Z] [WARN ] ice-extension-mngr-pool-1348 70002211 100161 200005 com.vmware.vise.extensionfw.impl.PackageManifestParser Plugin version mismatch for com.vmware.vum.client between the plugin registration info (6.8.4.00000)and the version specified in plugin-package.xml (6.8.2). The registration version will be used but you should keep them in sync.
[2019-02-06T22:33:59.431Z] [ERROR] ice-extension-mngr-pool-1348 70002211 100161 200005 com.vmware.vise.extensionfw.impl.PackagesDeployer Could not resolve dependencies for plugins packages: [ com.vmware.vum.client:6.8.4.00000 requires: [ com.vmware.vsphere.client.html greaterOrEqual 6.8.2 ]; ];
[2019-02-06T22:33:59.431Z] [INFO ] plugin-validation1 com.vmware.vise.extensionfw.impl.OsgiUsageValidationService Started validation of OSGi bad practices.
[2019-02-06T22:33:59.431Z] [INFO ] plugin-validation1 com.vmware.vise.extensionfw.impl.OsgiUsageValidationService OSGi validation skipped for plugin package com.vmware.vum.client:6.8.4.00000. It is not deployed.
I need to verify this same again but which plugin version has the registration which may not be compatible.
Can you try to re-register the VUM using the steps in below article and share the results
How do i reregister Update manager to my vcsa??
Note : Please take vcenter backup and snapshot before trying the above steps
Thanks,
MS