Error when trying to edit coupon

Just installed the awocoupon pro, created a coupon, but now I need to edit the coupon and all I get is the following whenever I try anything:

1271 Illegal mix of collations for operation 'UNION' SQL=SELECT a.coupon_id,a.asset_id,b.product_name AS asset_name,a.order_by FROM joom_awocoupon_asset1 a JOIN joom_hikashop_product b ON b.product_id=a.asset_id WHERE a.asset_type="product" AND a.coupon_id IN (1) UNION SELECT a.coupon_id,a.asset_id,b.category_name AS asset_name,a.order_by FROM joom_awocoupon_asset1 a JOIN joom_hikashop_category b ON b.category_id=a.asset_id AND b.category_type="product" WHERE a.asset_type="category" AND a.coupon_id IN (1) UNION SELECT a.coupon_id,a.asset_id,b.shipping_name AS asset_name,a.order_by FROM joom_awocoupon_asset1 a JOIN joom_hikashop_shipping b ON b.shipping_id=a.asset_id WHERE a.asset_type="shipping" AND a.coupon_id IN (1) UNION SELECT a.coupon_id,a.asset_id,b.coupon_code AS asset_name,a.order_by FROM joom_awocoupon_asset1 a JOIN joom_awocoupon b ON b.id=a.asset_id WHERE a.asset_type="coupon" AND a.coupon_id IN (1) UNION SELECT a.coupon_id,a.asset_id,b.category_name AS asset_name,a.order_by FROM joom_awocoupon_asset1 a JOIN joom_hikashop_category b ON b.category_id=a.asset_id AND b.category_type="manufacturer" WHERE a.asset_type="manufacturer" AND a.coupon_id IN (1)

Any help gratefully received.

Hello,

Never seen this problem in Hikashop before, only Virtuemart. Basically you will need to look at the database and figure out what is out of sync. I have a description here, which is for Virtuemart but should be easily translatable to work for Hikashop:
https://awodev.com/forum/awocoupon/help-section/error-showing-coupon-created-buy-one-get-one-half-price#comment-3880

If you prefer, I am happy to look at it directly if you send a private message with temp access.

Thank you, that seemed to do it.