Can not sync coreData

[avocet]

Dose Seam 3 have limit of syncing data ? I use seam 3 the sync data without problem in first 3 weeks, but after that, data cannot upload to iCloud and sync to another device.
Could you tell me where can I see the upload error notification ?
debug area shows below :
2018-09-25 11:57:18.925193+0800 operationSwift[48481:63391283] Cloud Sync Started
2018-09-25 11:57:28.182045+0800 operationSwift[48481:63391283] Cloud Sync Performed
2018-09-25 11:57:28.182192+0800 operationSwift[48481:63391283] Sync performed successfully

[avocet]

I can not upload new data to cloudkit. I found the error message from cloud kit dashboard as below:

error:BAD_REQUEST
operation:record modify
database:private
zone:SMStoreCloudStore_CustomZone
items:1
server latency:67ms
request size:1.04KB
response size:0B
hardware:iPad7,1
requestId:52E22FF3-7BAA-4AFD-8809-2003E08BE510

[avocet]

new error
The operation couldn’t be completed. (Seam3.SMStoreError error 4.)
What does it mean ?