Hi there!
We found an issue with the JA Payment Gateway plugin (version 1.1.6).
With the plugin we connected Mollie in test-mode.
While testing, we found out:
When I choose the option 'Succes' it works just fine. We are being redirected back to to the site from Mollie and the test payment is being processed.
However, when we simulate some other payment status, like canceled or failed, we are not redirected to the site but encounter a gateway-error. It looks like these 'unsuccesful' payment options are not correctly configured in the plugin.
Please can you try to simulate this on your end and let me know.
(ps. I searched for this plugin in your downloads section, to check if a new version was available, but can't find it!)