"Cannot resolve collation conflict" even after fixing the collation

The current database I'm using "PrimaryDatabase" has the collation "SQL_Latin1_General_CP1_CI_AS", while the "SecondaryDatabase" I'm trying to access has the collation "Arabic_CI_AS"

I changed the collation for the SecondaryDatabase and set it to " SQL_Latin1_General_CP1_CI_AS" and made sure it has been changed as well as in its tables.

However, when i run the query below I still get collation conflict.

select * from [MYSERVER].[SecondaryDatabase].[dbo].[SecondaryTableName] 
where ltrim(rtrim([SecondaryTablename])) not in (select ltrim(rtrim(PrimaryFieldname))  from PrimaryTablename where PrimaryFieldName2=1)