Windows Agent version mismatch:
Remote login to the Agent-installed machine ⇾ open Registry Editor ⇾ go to Computer\HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\ZOHO Corp\EventLogAnalyzer\LogAgent and ensure that the Agent version matches the Server version.
If there is a mismatch:
Remote login to the Agent-installed machine ⇾ go to Control Panel\All Control Panel Items\Programs and Features ⇾ uninstall the "ManageEngine EventLogAnalyzer Agent".