While changing from SSL to non-SSL LDAP configuration, the change appears to be working until the very end...
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Saving LDAP configuration ...
encountered a catastrophic error while running LDAP configuration. msg=: java.io.FileInputStream.open0(Native Method)
This is a defect were Changing from SSL to non-SSL where the previous "aaa.ldap.servercert.ca.fname" no longer exists on the filesystem throw this error.
There is a simple workaround on this if you can identify the filename of the server CA that is currently configured, and then simply create a file there so that ldap_config has something to load, that would allow you to move forward.
If you don't recall what the previously configured server CA file name please contact to Microfocus Support.