When trying to open certain Google Apps Script web apps on a mobile browser like Safari or Chrome (especially on iOS devices), you may encounter a generic error message: "Sorry, unable to open the file at present."
This is a common issue and it is not a bug in the web app itself. It is caused by a conflict between the enhanced privacy and security features of modern mobile browsers and the way Google handles user accounts.
Think of your mobile browser (like Safari) as a house with a very strict security guard.
Google's Login System: When you're logged into multiple Google accounts, Google often redirects you to a special URL (containing /u/1/ or /u/2/) to keep your sessions separate.
The Browser's Security Guard: The browser's security guard (its privacy features) sees this sudden redirect related to user accounts and thinks it looks suspicious, like a website trying to track you across different identities.
Access Denied: To be safe, the security guard blocks a critical piece of information (a cookie) during the redirect. Without that information, the Google Apps Script environment can't load the file, and it shows the error message.
This problem is most common on iPhones and iPads because their security and privacy protections are particularly strong.
If you're a user trying to access a web app, here are the most effective workarounds.
Solution 1: Use the official Google app (Recommended Workaround)
This is the easiest and most reliable solution. The official Google app doesn't have the same cross-domain security issues as a standard web browser.
If you don't have it, download the official Google app from the App Store.
Copy the web app's URL.
Paste the URL into the search bar inside the Google app.
The web app should open correctly because it's running within Google's own environment where your login session is already securely established.
Solution 2: Modify the web app URL
Where the original URL looks like this: https://script.google.com/macros/s/TOKEN/exec
For web apps owned by a personal account, Insert a/~/ between https://script.google.com/ and macros/
The final URL will look like this: https://script.google.com/a/~/macros/s/TOKEN/exec
For web apps owned by a Workspace account, Insert a/<DOMAIN>/ between https://script.google.com/ and macros/
The final URL will look like this: https://script.google.com/a/<DOMAIN>/macros/s/TOKEN/exec
The /a/ in a Google URL typically stands for "Apps," and it's used to route requests through the system for Google Workspace (formerly G Suite) accounts.
The ~/ is a special directive. In this context, it appears to tell Google's servers to run the script in a special, "agnostic" user mode. It essentially forces the script to run as a generic, consumer-level app and bypasses the complex authentication check that tries to figure out which of your multiple logged-in accounts (/u/0/, /u/1/, etc.) is the correct one.
Solution 3: Adjust Browser Settings (Use with Caution)
This solution can work but involves changing your browser's default privacy settings. It's not recommended to ask others to do this, but it can be an option for personal use.
Steps for iOS/iPadOS:
Open the Settings app.
Scroll down and tap on Apps.
Scroll down and tap on Safari.
Scroll down and tap on Advanced.
Find the toggle for Block All Cookies and turn it ON.
Close and reopen Safari, then try the web app link again.
This is a known issue with Google Apps Script Web Apps on mobile devices.
It happens because Google serves your script inside a security "Sandbox" (an <iframe>). Mobile browsers are very strict and often block this iframe from loading to prevent tracking, or it collapses the iframe height to 0 pixels, resulting in a blank white screen.
To fix this permanently, you need to do two things:
Code.gs: Add setXFrameOptionsMode(HtmlService.XFrameOptionsMode.ALLOWALL) to tell the browser it is explicitly allowed to display the app.
Index.html: Add min-height: 100vh to the CSS. This forces the app to take up 100% of the screen height so the browser cannot collapse it.