Buy X get Y

Is it possible that Buy X get Y and Buy A get B in the same coupon code?

Yes, you can create a combination coupon:

- Coupon A: buy x get y
- Coupon B: buy a get b
- Coupon C: combination coupon where you add coupons A and B, set process type to 'all that apply'

Then give out coupon C.

thank you

I don't know something went wrong. I reuse this condition again and got error " COM_VIRTUEMART_COUPON_CODE_INVALID ". Please advise. Thank you.

Not sure without alot more information.  In awocoupon > configuration > error messages, you can click the debug button and save, then you should get a more detailed response in the front end why a coupon fails.  If this is a combination coupon, try each coupon within the combination coupon individually to see the error.