Product license file fails to install due to invalid file permissions shows only a "timeout" error

Tested on CentOS 7

Given the following permissions on a .lic product license file:

[root@localhost nexus3]# ls -alh /home/dan/sonatype/product/*.lic
rwxr-x--. 1 root root 2.9K Jul 12 18:08 /home/dan/sonatype/product/sonatype-nexus-firewall-lifecycle-2017.lic

(only accessible by "root" user)

Seems a little odd that this file is visible to be selected in the web UI, but it is:

When you try to install this license via the UI, after 30 seconds, a "timeout message" appears in the UI and the nexus.log, but no indication of the cause of the failure is shown in UI nor in the log. Only the "timeout" message appears, which makes it hard to diagnose the real problem is with file permissions of the .lic file.

Maybe an issue with extjs upload feature?

Workaround: Granting higher access permissions to the .lic file solves the issue.