For anyone having the same issue I have got this working. I’m not entirely sure how but as there’s such little info about it and a couple of community posts with no solution here’s what the fields require exactly and what seemed to get it working for us.
Username: this is your Adyen webservice username in full (e.g. ws_123456@Company.YourCompanyAccount
Password: This is the Basic Auth password you can generate for the webservice user, NOT the API Key
Merchant Account: This is the Merchant Account the webservice user is created for, not your Company Account (e.g. YourCompanyAccountECOM, NOT YourCompanyAccount). You’re able to see this in the webservice user API Credentials section at the bottom of the page under ‘Accounts’.
Now I tried all sorts of combinations including those correct ones but all to no avail. What got it working I’m not sure but this is what I did immediately before in this specific order:
- Accessed the webservice user in Developers > API Credentials
- Copied the webservice username
- Generated a new API key and copied it
- Generated a new Basic Auth key and copied it
- Scrolled down to ‘Accounts’, expanded that section, copied the name of the account
- Hit Save
- Headed into Shopify Admin > Settings > Payments Adyen Manage
- Pasted the details mentioned above (specifically with Basic Auth as the password, NOT API Key)
- Hit Save
I then made an order and tried a payment and it worked.