Replace the battery - data can fail to transmit properly on a low battery. additionally, Actofit fitness doesn't recommend the use of any battery with a bitter/child deterrent coating. these batteries are not approved for use actofit devices and only be used at your own risk should you choose to use them. this coating has the potential to reduce the battery performance and may degrade sensor functionality. Actofit recommends using Panasonic / Sony coin- cell batteries or another name brand for optimal performance and tracking. 

Ensure pairing made only through app 

Check the Fit - ensure Actofit HRM monitor is worn snugly on the chest , directly against the skin for the best connection ( movement or slipping may disrupt readings) 

Check the battery connection - while the battery is removed , flex the metal prong that connects to the battery by pulling up gently. if the prong becomes pushed down too far , it can fail to make a strong connection with the battery. 

physical distance : signal strength degrades as distance increases. for best results, keep your device less than 5 feet from your monitor. 

Wireless signals : any devices that transmit wireless signals or electromagnetic fields can cause interference , especially these: 

1.wireless routers 

2.Wireless or Bluetooth headphones or speakers

3.Bike lights

4.Video recording devices (GoPro's, etc.)

5.Wireless video receivers or transmitters (Chromecast, Airplay, Roku, etc.) 

6.Fans (especially large ones):

7.Cordless home phones

8.Satellite or cable boxes

9.Microwave ovens

10.Power sources (power lines, boxes, lines in walls) 

11.Wireless mice/keyboards

12.Certain TVs (especially Wi-Fi Smart TVs) or monitors 

13.Anything else that can transmit wireless signals, including radios and baby monitors

Physical barriers: Walls, metal desks, and counters all degrade signal quality.