something wrong with the sniper system when I add an item number it does not take it and shows an error message that it is an invalid item number
I tried multiple items from multiple sellers, same error

Hello Arpad,
Thank you for your question about the "Invalid Item Number" message. We jumped on this issue as soon as you wrote and resolved it. Please let us know if you see it again.
Please let us know if you have any other questions, or require other assistance. We are happy to help.