This problem occurs because there are bugs in the latest update version of the default Android WebView System from Google, to solve the problem, please do the following instructions on below:

go to app/java/<package_name>/activities/ and find the files below :
1. ActivityStoryDetail.java

open the file above and find the code on below (Ctrl + F) :

.loadData(text, mimeType, encoding);

then, Replace All with the code on below (Ctrl + R) :

.loadDataWithBaseURL(null, text, mimeType, encoding, null);

Once you’ve reskin the project especially after package name / applicationId has been changed, the project structure will be changed, just replacing the updated files without having knowledge in Android Programming in advance will cause the project error dan failed to build the project, because of that, every we release the new update, you need to do reskin the application from begin, please note, update version is optional, update your application if you only find the issue from previous version or want to use all features from new version.

In the previous version, we implement Pdf Reader through WebView which integrated with google drive and this implementation is not good in user experiences, because of this reason, we implement build in Pdf reader inside the application using Android PdfViewer library and detail library can be read here, because Android PdfViewer depends on PdfiumAndroid, which is set of native libraries (almost 16 MB) for many architectures. Apk must contain all this libraries to run on every device available on market.