How do I bookmark the sms: scheme?
On Android the communication between the web browser and the sms app bases on &quot;Intents&quot;.
based on your description the problematic component in this set-up is the web browser.
Hence using a different app that can send Intents to other apps or using the adb shell can be helpful for testing out SMS links directly.
There a a lot of apps in Google PlayStore that can send Intents to other apps, for example Intent.
If you want to try adb (Android Debug Bridge) use the following command to sens an sms intent:
adb shell am start -a android.intent.action.VIEW -d sms:1234?body=5678