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Max. cable lengths for temperature sensor DS18B20

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I have connected a Shelly_AddOn with 5 DS18B20 temperature sensors.

Two sensors should be operated 15m away.
I laid an extra cable for the two long routes.

As soon as I connect this line to the Shelly_AddOn, the values of the other sensors are gone. The pure open line without sensors is sufficient if I only connect V+ and DATA.

Is there a maximum cable length for the Shelly/DS18B20?

By the way, you can also buy the DS18B20 with a 15m cable (unshielded).

Thanks for your help :-).

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I have no experience with 15 meters, my 8 pieces of 10 meter DS18B20 in my heater have been working for almost 2 years without any problems. (Gen1 old Add-On).
Since the measured values are transmitted digitally, the line resistance has no influence on the result.
At most, the voltage supply could become too low due to a voltage drop.
I think there shouldn't be any problems with 15 meters if they are installed at a distance from sources of interference.
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