Invoking Zoho Projects services via API failed, error 6501 returned

Invoking Zoho Projects services via API failed, error 6501 returned

Hi Zoho Projects,

I'm programming and testing Zoho Projects API. I have got apikey, also got the ticket following the instructions. However, when I try to invoke getportals service, I receive 6501 error ( Input Parameter Doesnt Match the Pattern Specified). Can anyone shred some light on this?

Here is the html I set up to invoke getportals service (apikey has been masked, not the real one):

<!DOCTYPE html>
<html>
<head>
    <title>Zoho getportals</title>
</head>
<body>
<input type="submit" value="Get Portals" >
</form>
</body>
</html>


Thanks,
- Terrence