AxiosError {message: 'Request failed with status code 405', ....
..........................

const handleUpdateAd = async () => {
    try {
      const res = await axios.put(`/api/advertisement?adId=${adId}`, {
        title: adTitle,
        link: adLink,
        image: imagePreview,
      });

      console.log("res of handleUpdateAd:", res);
    } catch (error) {
      console.log("error in updating ad:", error);
    }
  };

export async function POST(req: Request) {
  const body = await req.json();
  const url = new URL(req.url);
  const adId = url.searchParams.get("adId");

    if(adId){
      try{
          body.adId = adId;
          const ad = await updateAd(body);

          return NextResponse.json({message:'Advertisement Updated Successfully', advertisement: ad})

      }catch(error){
        console.log('error in UpdateAd post:', error);
      }
    }else{
      try {
        console.log("body:", body);
        const advertisement = await createAdvertisement(body);

        return NextResponse.json({
          message: "Advertisement created successfully",
          advertisement,
        });
      } catch (error) {
        console.log("Error in Post request while creating Advertisment:", error);
        // return NextResponse.error({message: 'Internal server error', error, status: 500})
      }
    }  

}

export async function updateAd(adData: any){
    try{
        const {adId, ...rest} = adData;
        const ad = await Advertisement.findByIdAndUpdate({_id: adId}, rest, {new: true});

        if(!ad){
            throw new Error('Advertisement is not updated');
        }

        return JSON.parse(JSON.stringify(ad));
    }catch(error){
        console.log('Error while updating Ads:', error);
        handleError(error);
    }
}