It would be good practice to prevent the phone from going on standby mode and keeping WhatsApp opened on your phone (the phone you paired with Mercury).
If your phone goes on standby while sending, it may cause messages to slow down. To prevent this delay, you can always keep the screen on.
It would also be good practice to keep WhatsApp opened on the phone when sending.
On Android there are some apps that allow to keep the screen on.
For example, we can suggest the Screen on app or other similar apps on PlayStore.
If you use an iPhone or another iOS device you can avoid the standby mode by the settings.
If you’ve decided to turn off Auto-Lock on your iOS device, you can do so by following these steps:
Tap Display & Brightness
Choose Never from the list of options.