If not, please take time follow the instruction below to work around this issue.
NOTE: before doing so, please make sure you had backed up your account.
1. Reboot your device, restart the internet connection, and relaunch the app.
2. Try to perform a Reset catalog multiple times.
3. Switch between other sources (preferably6 Manga Rock source).
4. If the issue still persists after, please try to log out and clear the app’s data (might risk current downloads).
5. Another solution is to just leave it be, for a while. Then try to relaunch the app.
6. Close cellular data and use only Wifi on your device.
Please let me know if one of the solutions provided above works.
Again if the issue is still there, please let me know the exact manga chapters.