The end portal frames have a wrong facing position, when I put 12 portal frames with the white dot of the ender eye pointing at the portal middle, the portal does not spawn, they spawn if the ender eye white dot is pointing outside the portal.
MC-177639
Incorrect facing position of end portal frames
Resolved
Invalid
0
You need to build the portal as described: https://minecraft.gamepedia.com/End_portal#Creation