In case the full-text search is not working properly, check if all subindices were created. Therefore, have a look into the WebOffice 10 R3 log file and search for an entry "FTS_SUBINDICES_PARTIALLY_MISSING".

WebOffice 10 R3 log file - FTS subindices partially missing
If an entry like in the image above exists, one or several subindices are missing. Navigate to the full-text search tab of SynAdmin where the state of the subindex mentioned in the log file is set to "missing". Create a new subindex an restart the application to refloat the full-text search.

SynAdmin - FTS subindex is missing