JWT signature verification failing

I am trying to implement my own auth using JWT tokens. I generate the jwt tokens in Java Spring boot.

Im using this website to generate a base64 encoded string to be used as the jwt secret: https://www.devglan.com/online-tools/hmac-sha256-online?ref=blog.tericcabrel.com

This is the relevant Spring boot code:

private Key getSignInKey() {
    byte[] keyBytes = Decoders.BASE64.decode(secretKey);
    return Keys.hmacShaKeyFor(keyBytes);
}

Jwts
        .builder()
        .setClaims(extraClaims)
        .setSubject(userDetails.getUsername())
        .setIssuedAt(new Date(System.currentTimeMillis()))
        .setExpiration(new Date(System.currentTimeMillis() + expiration))
        .signWith(getSignInKey(), SignatureAlgorithm.HS256)
        .compact();

Which works fine, the problem isnt here. The problem arises on the nextjs side where im trying to verify the jwt token i retrieve from the api after logging in:

export async function verifyAuth() {
  const token = cookies().get('user-token')

  if (!token) {
    return null
  }

  const jwtSecretKey = getJwtSecretKey()

  const { payload } = await jwtVerify(token.value, new TextEncoder().encode(jwtSecretKey))

  return payload as JwtPayload
}

This keeps throwing the following exception, allthough im using the same secret key generated by the website above (getJwtSecretKey just returns the env variable from .env and im using jose):

digest: "3414803446"

тип JWSSignatureVerificationFailed: signature verification failed

at async verifyAuth (./lib/auth.ts:74:25)

at async Home (./app/page.tsx:11:18)

What am i doing wrong here?