NinjaBryan Dec 01, 2009
In version 3.1, support for MerchantWARE was added. However, a bug will prevent you from using this gateway successfully. We have fixed the bug and support will be re-added in 3.2.

I'm getting this "Invalid credentials" message using iSwipe 3.6, iPhone 3.1.3

Hello Bob,
Sorry for the trouble. If you drop us an email at support@appninjas.com we can open a ticket and get this taken care of for you. I suspect I know what's going on but we don't want to post your login info and credentials on a public forum during our troubleshooting.
Thanks