DECLINED * SYSTEM PROBLEM =CANNOT PROCESS

I'm getting this error testing on the Canadian test gateway.  It seems like the first try each day succeeds, but after that, every try gets that declined error.

Request:

   

Response:

   

The ResponseCode is 078 and ISO is 09.  I'm not sure if this applies, but I looked up the ResponseCode and ISO code here:      https://developer.moneris.com/More/Testing/Financial%20Response%20Codes which says 'Duplicate transaction'.  I use a different order_id in each request, so I'm not sure what would make it think it's a duplicate transaction.  Perhaps that's not the right place to lookup ResponseCode?

I need more to go on, to understand why it's failing.

Any help would be appreciated.

Thanks,

   - Mark