Not able to set Chrome local storage in extension (undefined)

Not able to set Chrome local storage in extension (undefined)

I have a Chrome extension I’m trying to read and write to local storage with like this:

chrome.storage.local.set({lty_username: username}, function(){
    if (chrome.runtime.lastError) {
        console.error(chrome.runtime.lastError);
    } 
    else {
        console.log("Username saved: " + username);
    }
});

chrome.storage.local.get(["lty_username"]).then((result) => {
    alert("Value currently is " + result.key);
});

But when I read the same key/value set to local storage, it is always undefined. There are no errors in the console.

Here’s is my manifest.json file:

{
    "name": "name",
    "version": "1.0.0",
    "description": "description",
    "manifest_version": 3,
    "author": "author",
    "action":{
        "default_popup": "index.html",
        "default_title": "title"
    },
    "host_permissions": [
    "*://*.facebook.com/",
    "*://*.twitter.com/",
    "*://*.linkedin.com/",
    "*://*.nextdoor.com/",
    "*://*.instagram.com/",
    "*://*.reddit.com/",
    "*://*.quora.com/"
    ],
    "permissions": [
    "cookies",
    "storage"
    ]
}

I can’t figure out why values are not being set in local storage. Anyone know why?