Thank you for your post!
If you are using the trial of Actual ODBC Driver for Oracle you could be running into a limitation of the trial drivers.
Aside of that, you will want to verify the FileMaker Server and Oracle are on separate machines.
You may also want to confirm that the database still works from your desktop. I ran around in circles a few years back with a similar problem only to discover the Oracle DBA had changed the password.
I know the limitation is just on a 3 row result when you execute any query, so I see over than 900 record but I can use just 3
from my desktop I confirm that I can do anything, of course just the first three row for the trial limitations but I can count all the records.
Something is different with ODBC driver on the server. Check if it is 64bit.
A couple years ago I spent about a week trying to get the server to connect to an Oracle DB. It would connect but my scheduled script wouldn't import records. Turns out that the server needed both a 32 bit DSN and a 64 bit DSN named identically because while the database itself was 64 bit the scripting engine was 32 bit.
This was FM Server 13. I don't know if this condition exists on later versions.
The following link suggests the scripting engine (fmsase[d]) is 64 bit in 13 and later versions of FileMaker Server.
Probably the problem is the desktop version and not the server one.
Next week I'll try again with a correct license.