Update: The issue has been resolved with the latest update (version 101.0.1). Please make sure you download the latest version from the App Store. This update resolves the issue from all Apple Watch devices, including Apple Watch Series 0.
We are investigating an issue that prevents the Strava Apple Watch from opening, recording, or is causing the app to crash. If you're experiencing any of these issues, please make sure you have updated your iPhone and Apple Watch to the most recent software using these instructions. The most recent Apple Watch OS can be found here. If you are using an older Apple Watch (Apple Watch Series 0) that cannot update to the latest OS (OS 5 or higher), we will be releasing a fix in version 101.0.1 and we appreciate your continued patience.