It has always been difficult or impossible to cash a US check in Europe, unless you make a specific arrangement with a local institution.
One travel site I frequent suggested going to a Citibank office in Hungary, since Citibank (as a US company) obviously has the wherewithal to process a US check if it so chose to.
Please see https://citibank.banklocationmaps.com/hungary/budapest for Citibank locations in Budapest.
