I worked for a few days and everything worked normal, until today, ran the command react-native run-android and the error happened, as if he did not find the project ... I updated the watchman, but the error persists...

I opened issue in the react-native, but reported to me that this would be a Watchman issue.... :(
Possibly a case sensitivity issue? Does https://stackoverflow.com/questions/35715904/react-native-watchmanresponse-unable-to-resolve-root sound similar, and does the resolution also solve your issue?
@alexandref93
Which version of Node.js are you using?
Maybe updating React Native to the latest one... 馃
in fact, it was just rename the folder to downcase... resolved
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in fact, it was just rename the folder to downcase... resolved