> ## Documentation Index > Fetch the complete documentation index at: https://docs.sonohealth.com/llms.txt > Use this file to discover all available pages before exploring further. # Home Blood Pressure Monitor Troubleshooting > Error messages, wildly different readings, cuff problems, and other common home blood pressure monitor issues — what causes them and how to fix them. Most home blood pressure monitor "problems" come from technique, cuff fit, or movement — not a broken device. Sit still and quiet, rest your arm at heart level, refit the cuff snugly on a bare upper arm, and retry after a minute; that resolves the majority of errors and odd readings. Troubleshooting is about getting a reliable reading, not interpreting one. If your numbers are genuinely high or you see an irregular-heartbeat flag, that's a question for your clinician — see [when to worry](/blood-pressure/high-blood-pressure-when-to-worry). ## Why is my monitor showing an error instead of a reading? Automatic monitors show an error when they can't get a clean measurement. The usual causes are moving or talking during the reading, a cuff that's loose or positioned wrong, an arm that isn't at heart level, or a very irregular pulse. Fix it by resting five minutes, sitting with your back supported and feet flat, wrapping the cuff snugly on a bare upper arm about an inch above the elbow crease, and staying still and silent while it inflates. If a specific error code keeps appearing, check the device manual and contact SonoHealth support. ## Why are my readings so different each time? Blood pressure genuinely changes minute to minute with activity, stress, caffeine, position, and time of day, so some variation is normal. To get comparable numbers, [measure the same way each time](/blood-pressure/how-to-measure-at-home): same arm, same posture, same time of day, after resting. Take two or three readings a minute apart and average them rather than trusting a single value, and compare [morning vs evening](/blood-pressure/morning-vs-evening-readings) consistently. ## My reading seems far too high or too low First rule out the cuff: a cuff that's [too small reads falsely high and one that's too large reads falsely low](/blood-pressure/cuff-size-and-accuracy), and placing it over clothing skews the result. Then confirm your arm was supported at heart level and you were rested — a dangling arm or a full bladder can shift the number. If a reading looks alarming, sit quietly and re-measure after a minute before acting on it. ## The cuff won't inflate or feels too loose or tight Make sure the cuff tube is fully seated in the monitor and the cuff is wrapped snugly — you should be able to slip one or two fingertips under the edge. If it inflates but immediately deflates or errors, the cuff is likely too loose or your arm moved. Confirm your [arm circumference falls within the cuff's range](/blood-pressure/cuff-size-and-accuracy); if it doesn't, you need a properly sized cuff. ## Does the SonoHealth BPpro or BPMAX need an app to work? No. Both are standalone upper-arm monitors — results appear on the display (the [BPMAX also reads them aloud](/blood-pressure/talking-blood-pressure-monitor)) and save to built-in memory, with no phone, app, or Wi-Fi required. If a monitor won't power on, check or replace its batteries before assuming a fault, then contact support. ## Home monitor vs the pharmacy machine or clinic It's common for your home reading to differ from a pharmacy kiosk or clinic. Kiosk cuffs are one-size and often fit poorly, and you're usually not rested. A properly fitted home monitor used with good technique is generally more consistent — to check yours, compare a home reading against your clinic's on the same arm. Persistent large gaps are worth mentioning to your doctor. For more on validation and what really drives accuracy, see [are home blood pressure monitors accurate](/blood-pressure/are-home-blood-pressure-monitors-accurate). ## When to stop troubleshooting and call your doctor Contact your doctor if your readings are consistently at or above 130/80, if you repeatedly see an irregular-heartbeat flag, or if the device still won't give a plausible reading after you've corrected technique and cuff fit. Treat a reading at or above 180/120 with symptoms as a medical emergency — call 911. *** **Related:** [How to Measure at Home](/blood-pressure/how-to-measure-at-home) · [Are Home Monitors Accurate?](/blood-pressure/are-home-blood-pressure-monitors-accurate) · [Cuff Size and Accuracy](/blood-pressure/cuff-size-and-accuracy) · [Upper-Arm vs. Wrist](/blood-pressure/upper-arm-vs-wrist) · [Irregular Heartbeat Detection](/blood-pressure/irregular-heartbeat-detection) · [How Often to Check](/blood-pressure/how-often-to-check-blood-pressure-at-home) · [When to Worry](/blood-pressure/high-blood-pressure-when-to-worry) · [BPpro vs BPMAX](/blood-pressure/bppro-vs-bpmax)