Able to GET in Postman, but not in browser - api

Question

Developing a React app and when calling the API in browser I receive a 404 error on the call, though the rest of the page renders successfully:
However, calling the same route in Postman returns successful:
It's not unique to this single route. Other API calls previously working through browser are resulting in the same error while calls through Postman continue to be successful.
Package.json for reference:
{
"name": "frontend",
"version": "0.1.0",
"private": true,
"dependencies": {
"#testing-library/jest-dom": "^5.11.9",
"#testing-library/react": "^11.2.3",
"#testing-library/user-event": "^12.6.2",
"axios": "^0.21.1",
"react": "^17.0.1",
"react-alert": "^7.0.2",
"react-alert-template-basic": "^1.0.0",
"react-bootstrap": "^1.4.3",
"react-dom": "^17.0.1",
"react-helmet": "^6.1.0",
"react-redux": "^7.2.2",
"react-router-dom": "^5.2.0",
"react-scripts": "4.0.1",
"redux": "^4.0.5",
"redux-devtools-extension": "^2.13.8",
"redux-thunk": "^2.3.0",
"web-vitals": "^0.2.4"
},
"scripts": {
"start": "react-scripts start",
"build": "react-scripts build",
"test": "react-scripts test",
"eject": "react-scripts eject"
},
"eslintConfig": {
"extends": [
"react-app",
"react-app/jest"
]
},
"browserslist": {
"production": [
">0.2%",
"not dead",
"not op_mini all"
],
"development": [
"last 1 chrome version",
"last 1 firefox version",
"last 1 safari version"
]
},
"proxy": "http://127.0.0.1"
}