A bug persists through iOS 14, which is causing Seamless for iOS to crash when uploading big files. We have provided a bug report to Apple and will increase the limit once the bug is fixed.
Please confirm if “Accessibility” is enabled for Seamless. Go to System Preferences > Security & Privacy > Privacy > Accessibility. See if Seamless is in the right panel list and the checkbox is selected. If isn’t, add Seamless to the list and select the checkbox.
This is a bug we can’t fix for the time being.