Prod Build Failed with ERROR in Cannot determine the module

sajith@sajith-G41MT-S2 ~/software/mdb-angular-pro-4.0.1 $ ng build --prod --aot Hash: 9e5d2e6fd57b766598c6 Time: 47639ms chunk {0} polyfills.e5f9b9b5b3ce20cb89b5.bundle.js (polyfills) 285 kB {5} [initial] [rendered] chunk {1} scripts.3bd5aa2f5fc8c4cdff58.bundle.js (scripts) 160 kB {5} [initial] [rendered] chunk {2} styles.883ae59ed7bb2f1e53c1.bundle.css (styles) 175 bytes {5} [initial] [rendered] chunk {3} main.24db8880874af18d6b76.bundle.js (main) 668 bytes {4} [initial] [rendered] chunk {4} vendor.f3860eb56332a43ff8a4.bundle.js (vendor) 848 kB [initial] [rendered] chunk {5} inline.a121fa953aa56bb5e34d.bundle.js (inline) 0 bytes [entry] [rendered] ERROR in Cannot determine the module for class doubleNav in /home/sajith/software/mdb-angular-pro-4.0.1/src/app/typescripts/angular-bootstrap-md/pro/doubleNavigation/doubleNav.page.ts! Add doubleNav to the NgModule to fix it. ERROR in ./src/main.ts Module not found: Error: Can't resolve './$$_gendir/app/app.module.ngfactory' in '/home/sajith/software/mdb-angular-pro-4.0.1/src' @ ./src/main.ts 4:0-74 @ multi ./src/main.ts

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