npm run build -- fails

[Serge-Libotte]

Error: Cannot find module '...\appAuthHelper\appAuthHelper$BABEL_ENV.js' from '...\appAuthHelper'
at ...\appAuthHelper\node_modules\browser-resolve\node_modules\resolve\lib\async.js:55:21
at load (...\appAuthHelper\node_modules\browser-resolve\node_modules\resolve\lib\async.js:69:43)
at onex (...\appAuthHelper\node_modules\browser-resolve\node_modules\resolve\lib\async.js:92:31)
at ...\appAuthHelper\node_modules\browser-resolve\node_modules\resolve\lib\async.js:22:47
at FSReqCallback.oncomplete (node:fs:203:21)