A certificate of occupancy shall be deemed to authorize and is required for both initial and continued occupancy and use of the building or land to which it applies, and shall continue in effect so long as such building and the use thereof or the use of such land is in full conformity with the provisions of this chapter, and any requirements made pursuant thereto. However, on the serving of notice of any violation of any provisions or requirements with respect to any building or the use thereof or of land, the certificate of occupancy for such use shall thereupon, without further action, be null and void, and a new certificate of occupancy shall be required for any further use of such building or land.