Hi @namlu ! This usually happens to me when I was working without an internet connection at some point and Android Studio switched me to offline mode. To make sure it’s not that, in your demo project choose Android Studio ▸ Preferences. On the left side choose Build, Execution, Deployment ▸ Build Tools ▸ Gradle. Uncheck the Offline work checkbox and then choose Apply or OK.
Other options are to try File ▸ Invalidate Caches / Restart …. If that still doesn’t work, try to clean up the .gradle and .idea directory under the project root directory. Let me know if that works.
Thank you @nsdestr0yer. I found those solutions via StackOverflow but still didn’t work for me. I gave up for a while and recently solved it by deleting my gradle.properties using $ rm ~/.gradle/gradle.properties