"The OVF package is invalid or could not be read."It sounds like corrupted file but it is very rare as it was successfully downloaded directly from my.vmware.com.
I have double checked download and quickly realize what is wrong. OVF file should be XML file with references to vmdk files (disk images) but this OVF file was just a single large file. The single large file is typically OVA which is an archive of OVF. OVA is nothing else then zipped TAR (aka tgz). I tried to rename file to .tgz, extract the file and voila ... there was real OVF and VMDK file. See. screenshot below
Deployment of real OVF (ovf descriptor + vmdk files) was successful so it is workaround #1.
Workaround #2 is just renaming file extension of downloaded OVF file (VMware-NSX-Manager-6.2.4-4292526.ovf) to OVA (VMware-NSX-Manager-6.2.4-4292526.ova) and deploy OVF/OVA again.
Hope this helps others struggling with virtual appliance deployment when OVF and OVA file extensions will be interchanged.
Note: I have double checked my.vmware.com and NSX Manager 6.2.4 is downloadable as file with .OVA extension so it was most probably already identified and repaired by VMware or something else weird happened during my download several days ago.