Anyone else getting an error when trying to access the mobile version? from LegendsOfRuneterra
Storage Permission
Every app asks for permission to interact with your phone’s hardware—for instance, Storage, Microphone, Camera, etc. The so-called permissions to be allowed for the specific app for it to function properly. If you didn’t allow Storage permission for Legends of Runeterra, then the game won’t be able to download files and store on your phone.

To allow storage permission Go to Settings>Apps and Notification > See all apps, then tap on our game and then tap on Permissions. Then enable Storage permission from there. This option may vary based on your phone; for some phones, you have to turn on the toggle switch; for some, you have to tap and select enable.
Check Pre-requirements
For the update to complete the update, your phone has to be in condition. You should have enough space left on your phone. Also, you should have at least 1GB of RAM free on your phone to enjoy the game. As you already know that internet connection is a must for the update to download, the connection should be stable and fast in order to download the update. So check on these facts and confirm everything meets the requirements.

Background Apps
Some background apps running on your phone will interfere with the update process either by taking up system resources or by consuming most of your bandwidth. Close all unnecessary apps running in the background like Spotify, Whatsapp, Facebook, etc. and try the update process.

To close an app, Go to Settings>Apps and Notification > See all apps. Then, tap on the app you wish to close and click on Force stop.
Clear the app Data
Clearing an app’s data will solve many issues. This clears any data that is corrupt, which prevents the smooth operation of the app.

To clear the app data, go to Settings > Apps and notifications > All apps and tap on Legends of Runeterra and tap on storage, then tap on Clear Storage. It is also recommended to Force stop the app before clearing the data to relaunch the app in a new state.
Reinstall the app
If none of the above methods worked for you, the final solution is to reinstall the game. Go to app details as mentioned above and click on Uninstall. Now Open play store and Search for Legends of Runeterra, now click on install. This will reinstall the game. Once you’ve downloaded, launch the game, and it will start to update your game. Wi-fi connection is recommended, but you can also use Mobile Data if you wish.

App source
If you installed any app from unknown or untrusted sources other than the play store, the game would not work properly. It won’t also work in case of modded apps that you get from the web.
[googleplay url=”https://play.google.com/store/apps/details?id=com.riotgames.legendsofruneterra&hl=en_IN”]
Hence it is always recommended to obtain apps or games from the play store or your manufacturer’s app store. The apps obtained outside the store may contain malware that may cause problems on your device. Your device will be vulnerable if you sideload such untrusted apps.
Conclusion
So, these were the solutions to the update related issues with the Legends of Runeterra game for mobile. I hope your issue is solved. If these don’t fix your issue, then it’s an app-related bug that you might need to notify to the developer to fix the issue. Contact Riot games developer details are provided in the Google play store.