I have a question when I work on Linkedserver

The Linkedserver name is [Hp-server],the Datebase name is
Newexec,the Table name is Customers_CoypTest

The SQLScript is below:

Update [Hp-server].Newexec.dbo.Customers_CoypTest
set Unitname=b.Unitname
from [Hp-server].Newexec.dbo.Customers_CoypTest a join
Newexec.dbo.Customers_CoypTest b
on a.Cid=b.Cid and b.Cid='Tony'

The server returns ERROR like this:

a) can not open this table '"Newexec"."dbo"."Customers_CoypTest"'
(come from OLE DB provide server 'SQLOLEDB'). provide server do not
support index scan on the data source.

b) [OLE/DB provider returned message:Error occured when
multi-operate.If possible, please check each OLE DB status value.No
work had been completed.]

c) OLE DB Error trace[OLE/DB Provider 'SQLOLEDB'
IOpenRowset::OpenRowset returned 0x80040e21:
[PROPID=DBPROP_COMMANDTIMEOUT VALUE=600 STATUS=DBPROPSTATUS_OK],
[PROPID=Unknown PropertyID VALUE=True STATUS=DBPROPSTATUS_OK],
[PROPID=DBPROP_IRowsetIndex VALUE=True
STATUS=DBPROPSTATUS_NOTSUPPORTED]].