Hi, and welcome.
I took a look at your listing. You will need to redo your title and i believe you have selected the wrong subcategory for your set. You are offering more than just the motherboard. Review other sellers’ listings to see how they word their titles. I couldnt tell what you were selling until i read the description.
When i followed your link, it took me to eBay Canada, not the USA eBay.com site where you have posted your question. I don’t see your listing here on the US site. You might have better luck posting your question to the Canadian forum to discover the ins and outs of international selling. Generally new sellers must have some more experience before eBay allows it but i don’t know what the rules are for eBay Canada.
Before you go any farther, i want to urge you to reconsider selling an expensive computer gaming set as a new seller here. It is possible for someone to defraud you by claiming Item Not As Described and then returning an empty box, where you will lose the funds and the items. New sellers of expensive items sometimes get targetted and there is virtually little to be done to protect yourself from this risk. I see that you have an established German eBay account and are therefore not wholly inexperienced. You might do better selling your item locally for cash or waiting to sell when you return to Germany.