The problem could be customs. When I am outside of the US, some shipments seem to get lost coming to me or being sent back stateside. I have found that some packages just get held or “bonded” by customs for inspection, duty, documentation, or suspicious contents.
The package will be held at the air or sea port (yes, I have shipped a few 40 foot containers) but tracking will say that it hasn’t arrived because it doesn’t count as being in the destination country until it clears customs. Same holds true for people travelling internationally. What was that Tom Hanks movie called?