Phone calls on your Android phone will stop a video recording that's in progress, in the Sibme app. When this happens, no error message will appear but the video will stop recording, regardless. To prevent this from happening you can set your Android phone to 'Do not disturb'. Different Android devices name this setting slightly differently.
The example below demonstrates how to do this on an Android Galaxy S7 Edge. The exact screens and exact naming of items will vary from brand to brand but should be very similar, regardless.
Open settings on your Android phone.
In 'Sounds and vibrations,' enable 'Do not disturb.'
Make sure you don't allow exceptions.
You may also find the 'Do not disturb' option, if you drag your thumb down from the top edge of your screen. Note that some phones have an 'Airplane mode' available in this area, instead. Airplane mode will disable WiFi, which will prevent your video from auto-uploading and will prevent Sync Notes from working properly, so you may want to find 'Do not disturb' in settings instead.
Please make sure to keep the notification pop-ups turned off so that it cannot interrupt your recording.