Why is my app setup failing in Shopify tutorial?

[GottaMinute]

I'm going through the Shopify Create an app tutorial and on the last step to test the App it's failing. When I click the save button nothing happens and in the console I see these errors...

POST https://monorail-edge.shopifysvc.com/v1/produce net::ERR_BLOCKED_BY_CLIENT

and...

Uncaught Error: Error completing request. A network failure may have prevented the request from completing. Error: TypeError: Failed to fetch
at new t (vendors-node_modules_bugsnag_js_browser_notifier_js-node_modules_shopify_monorail_lib_monorai-3c804f-516a5b5ebea88fcd3958aad35dd2613df20887a0fdc79df5782663ddb5d0c6ed.js:2:70672)
at e.<anonymous> (vendors-node_modules_bugsnag_js_browser_notifier_js-node_modules_shopify_monorail_lib_monorai-3c804f-516a5b5ebea88fcd3958aad35dd2613df20887a0fdc79df5782663ddb5d0c6ed.js:2:66965)
at vendors-node_modules_bugsnag_js_browser_notifier_js-node_modules_shopify_monorail_lib_monorai-3c804f-516a5b5ebea88fcd3958aad35dd2613df20887a0fdc79df5782663ddb5d0c6ed.js:2:270920
at Object.throw (vendors-node_modules_bugsnag_js_browser_notifier_js-node_modules_shopify_monorail_lib_monorai-3c804f-516a5b5ebea88fcd3958aad35dd2613df20887a0fdc79df5782663ddb5d0c6ed.js:2:271025)
at a (vendors-node_modules_bugsnag_js_browser_notifier_js-node_modules_shopify_monorail_lib_monorai-3c804f-516a5b5ebea88fcd3958aad35dd2613df20887a0fdc79df5782663ddb5d0c6ed.js:2:269815)

Can someone lend a helping hand please.

[GottaMinute]

I fixed these errors by allowing popups! I did realize pops were getting blocked.

Now I'm getting this error...

backend | (node:29772) UnhandledPromiseRejectionWarning: Error: Received an error response (406 Not Acceptable) from Shopify:
backend | If you report this error, please include this id: 3cb250ec-edc8-4b44-816e-666892a4ad36
backend | at HttpResponseError.ShopifyError [as constructor] (H:\100Devs\shopifyV2\qrcode\qrcode\web\node_modules\@shopify\shopify-api\dist\error.js:13:28)
backend | at new HttpResponseError (H:\100Devs\shopifyV2\qrcode\qrcode\web\node_modules\@shopify\shopify-api\dist\error.js:104:28)
backend | at HttpClient.<anonymous> (H:\100Devs\shopifyV2\qrcode\qrcode\web\node_modules\@shopify\shopify-api\dist\clients\http_client\http_client.js:248:43)
backend | at step (H:\100Devs\shopifyV2\qrcode\qrcode\web\node_modules\tslib\tslib.js:144:27)
backend | at Object.next (H:\100Devs\shopifyV2\qrcode\qrcode\web\node_modules\tslib\tslib.js:125:57)
backend | at fulfilled (H:\100Devs\shopifyV2\qrcode\qrcode\web\node_modules\tslib\tslib.js:115:62)
backend | at processTicksAndRejections (internal/process/task_queues.js:95:5)
backend | (node:29772) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). To terminate the node process on unhandled promise rejection, use the CLI flag `--unhandled-rejections=strict` (see https://nodejs.org/api/cli.html#cli_unhandled_rejections_mode). (rejection id: 12)

hmmmm

[rorydean]

Hey @GottaMinute I realize this is several months old now but did you ever discover what was causing that issue?  I've been experiencing some very peculiar anomalies with cache files, page loads and updates after making changes and I've noticed repeat messages referring to '...monorail...'.  I am not an app developer and only have a few apps running on our site but when I searched for answers I found your threat. Let me know if you have any further thoughts. Thanks-

[greekfreak_034]

Hello! Currently I encounter this error in my app extension using React. I installed an image editor on the extension and when I navigate and add stickers (a .png) this error occurs. May I know if you solved this problem badly needed it. Thanks!