Canada Post returns this error when it cannot bill the label to your Canada Post account. SKULabs asks Canada Post to charge each label to your Canada Post account (method of payment: Account), so this error means Canada Post refused that payment method for your account.
Why did I get "Method of payment Account is not available"?
The payment method on your Canada Post account is not valid for the API credentials saved in SKULabs. Common reasons:
The payment method on your Canada Post account was removed, expired or unlinked.
Your account has an unpaid balance or has reached its credit limit, so it is not in good standing.
The credentials saved in SKULabs need to be updated.
How do I fix it?
Sign in to your Canada Post business account and check that your account information is current and there is no outstanding balance.
Enter your payment method again in case it was unlinked.
If your credentials changed, update them in SKULabs: go to Settings > Shipping > Carrier accounts, click the pencil (edit) icon on your Canada Post account, update API Username (Production Only) and API Password (Production Only), then click Save.
Try the label again.
My credit card works for other purchases. Why is it failing now?
Contact your card provider. Multiple failed attempts, often caused by reaching the credit limit, can block the card for these charges. You can also add a different card. Any outstanding balance must be paid before Canada Post will bill new labels.
What if the problem continues?
Contact Canada Post to confirm your account and payment method are set up for shipping through the API. If you need help in SKULabs, contact support through live chat or at support@skulabs.com.