###The texture might be tiled.

To change:

1. Go to PROPERTIES PANEL --> "Active Tool & Workspace Settings" (the screwdriver & wrench)

###2. Find the TEXTURE TAB --> Change MAPPING from "TILED" to "STENCIL"

After this change, my texture was visible in viewport:

I ran into a similar problem doing a Blender 2.8 sword tutorial on youtube. Answer credit goes to the comment section of that tutorial:

The texture might be tiled.

To change:

1. Go to PROPERTIES PANEL --> "Active Tool & Workspace Settings" (the screwdriver & wrench)

2. Find the TEXTURE TAB --> Change MAPPING from "TILED" to "STENCIL"

After this change, my texture was visible in viewport:

I ran into a similar problem doing a Blender 2.8 sword tutorial on youtube. Answer credit goes to the comment section of that tutorial: