Seafile Sync Issue!

Hey!
I am using Seafile with another offsite backup solution. This is to ensure extra protection in case of an emergency. I have The trouble here is that, occasionally when both of these syncs together, seafile aren’t syncing some files. I am unable to find these files using android or iOS apps. What can be the issue? How can I solve it? Hoping for a resolution as soon as possible.
Thanks!