This KB article will helps you to understand why application image upload is failing on 24.1R2.15 or NMP 24.1R3.16 setup

Security Director application image upload is failing on 24.1R2.15 or NMP 24.1R3.16 setup with an error "Software validation failure, check certificate keys"

Below error can be seen under server.log

==> /var/log/jboss/servers/server1/server.log <==
/var/log/jboss/servers/server1/server.log.2:2025-01-24 04:08:44,912 INFO  [net.juniper.jmp.cmp.resourceDistributionManager.ejb.softwareManager.SoftwareManagerBean] (JobThread262144) checkSwUploadVersion: response = <response>
/var/log/jboss/servers/server1/server.log.2-<message><![CDATA[/usr/bin/extract_image.sh -i '/tmp/jmp/Security-Director-24.1R2.62/Security-Director-24.1R2.62.img' -s /etc/pki/jmp-softwareManager/certs/JunosSpaceSoftwareCA_v1.pem -t /etc/pk
i/jmp-softwareManager/certs/JunosSpaceTrusted_CAs.pem -d /tmp/jmp/payloads
/var/log/jboss/servers/server1/server.log.2-.]]></message>
/var/log/jboss/servers/server1/server.log.2-<errorcode>256</errorcode>
/var/log/jboss/servers/server1/server.log.2-<status>FAILURE</status>
/var/log/jboss/servers/server1/server.log.2-</response>
/var/log/jboss/servers/server1/server.log.2:2025-01-24 04:08:44,912 ERROR [net.juniper.jmp.cmp.resourceDistributionManager.ejb.softwareManager.SoftwareManagerBean] (JobThread262144) checkSwUploadVersion: response = failure for node = space-005056a9e159
/var/log/jboss/servers/server1/server.log.2:2025-01-24 04:08:44,912 ERROR [net.juniper.jmp.cmp.resourceDistributionManager.ejb.softwareManager.SoftwareManagerBean] (JobThread262144) checkSwUploadVersion: errorcode = 256
/var/log/jboss/servers/server1/server.log.2-2025-01-24 04:08:44,912 INFO  [net.juniper.jmp.cmp.resourceDistributionManager.SoftwareManagerUtils] (JobThread262144) SaveFile: return status for checkVersion = 3

Junos Space 24.1R2 Patch V1 Patch has been released on Juniper support portal. You can apply it to fix the application image upload issue. Patch can be downloaded from below URL. 

If you are already on 24.1R3.16 NMP version, then you can also apply the Junos Space 24.1R3 Patch V1 as well.

https://support.juniper.net/support/downloads/?p=junos-space-network-management-platform

Note : If you face any further issues, please contact JUNIPER JTAC Support for assistance.