Sometimes a user will set a Custom voicemail greeting (under Messages & Notifications) but when they test it or when people call it, they are not hearing the Custom voicemail greeting that was uploaded. Why?
The 1st to check is What are your User Hours set for?
2nd What timezone is the User set for?
3rd thing to check is Is the Custom Voicemail uploaded for User Hours or After Hours?
In this setup above, if you are calling/testing at 9:15am in Mountain Time (it's 8:15am Pacific Time) therefore the caller will get the After Hours voicemail that is still set for Default under Messages & Notifications. That is why the caller/tester is hearing the Default and not the Custom voicemail.