Tried the following
and "it works" on my computer (Ubuntu 18.04), so clearly and environment issue (Dotnet level or more probably libcurl dll). You may try using this HTTPS URL to see if it changes from the ...
The code in the data callback is asynchronous and won't run until after the console.log. Also you have redeclared ndvi_20200706 by using var in the callback
You could simply set a timeout and hope all your results are in after 5 seconds
var viewResolution = view.getResolution();
var ndvi_array = , ndvi_20200706, ...
var url_20200706 = ...
You would get more control loading via xhr as in https://openlayers.org/en/main/apidoc/module-ol_Tile.html#~LoadFunction and scheduling a retry from the the xhr's error/timeout handler.
No error handling should be needed once you have an object url, but to avoid memory leaks
tile.getImage().src = URL.createObjectURL(data);
should be replaced by
var url = ...
shp2geojson.js can take a File object as url, so you could simply drag and drop zipped shapefiles onto the map from a network drive http://mikenunn.16mb.com/demo/shp.html
<title>Load SHP overlay</title>
<link rel="stylesheet" href="https://openlayers.org/en/v6.3.1/css/ol....
Using QGIS (3.14) WMS
There are two
CHS NONNA-100 Bathymetric Data / Les produits de données
bathymétriques NONNA-100 du SHC