Short answer: Turn the Out-Of-Date (OOD) checkbox ON. The checkbox is located in the upper right corner of your Add-ons list. Then QUIT and restart the game.
Long answer: The manifest file, "LibMapPins-1.0.txt" is woefully Out-Of-Date. You should make a backup copy of the manifest file before you edit the file to change the "## APIVersion:" directive value from "100019" to "100027 100028". That should fix major problem.
Before you do that, you might wish to read the ESOUI wiki sections about add-on "Packaging". You can find that information
here and
here. These two sections should help you discover the other packaging oversights in this add-on.
This is what my version of the manifest file looks like. You can look at it as an example but you should not copy nor use it because I have changed the folder packaging to match my manifest file changes:
Code:
## Title: LibMapPins 1.0 r17
## APIVersion: 100026 100027
## AddOnVersion: 17
## Version: 1.0 r17
## DependsOn: LibStub
## IsLibrary: true
## Author: Garkin, (modified by Sensi)
LibMapPins-1.0.lua
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; registered trademarks or trademarks of ZeniMax Media Inc. in the United
; States and/or other countries. All rights reserved.
;
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