When sync Public Folders from On-Premise Exchange to Office 365. It extracts the data from the source public folders, but when attempting to write the information to Office 365 it get the following error in the Mail Target Agent (MTA) log:
-2147220477 Too many names have been found in the directory service or the server has exceeded its time limit for searching. Type more letters of the name and try again. -MAPI_E_TABLE_TOO_BIG.
This had been fixed in the latest Migration Manager for Exchange 8.14 hotfix. The latest Migration Manager hotfix can be downloaded from KB77417