No problem is an English expression, used as a response to thanks (among other functions).
In the culture of younger Americans, no problem is often used as a more conversational alternative to you're welcome.
[1] It is widely believed that younger speakers especially favor no problem over you're welcome, and empirical research has corroborated this belief.
[4] An early example appears in a 1959 edition of the American Import and Export Bulletin, with an advertisement stating: "Foreign shipping is No Problemo".
Many Spanish words from Latin roots that have English cognates have an -o in Spanish from the masculine Latin suffix -us, such as "insect" (insecto), "pilot" (piloto), and "leopard" (leopardo); however, "problem" belongs to the group of words ending with an a in Spanish that have a similar English counterpart, such as "poet" (poeta), "ceramic" (cerámica) and "rat" (rata).