unable to browse 2008 sysvol from 2019 DC

I am getting an login prompt and "Access is denied." message when trying to browse \\2008DC\sysvol from a newly built 2019DC.

1. We have an old test environment with 2008 DC (single DC and not R2 version).
2. The forest level was increased to 2008 and FRS migrated to DFS-R.
3. New 2019 box promoted to DC with no issues.

Any idea what may be causing the prompts?