BootStrapped SCM fails to bootstrap if it connects to another bootstrapped SCM first.

GetSCMCertificate can happen non-leader SCM, as rootCA is only run on primary SCM.
So, when an SCM is bootstrapped, let's say it connects first to a bootstrapped SCM, we fail with a SCMSecurityResponse with status set to NOT_A_PRIMARY_SCM. As we return with a response, failOver will not happen.

SCMSecurityProtocolClientSideTranslatorPB

  private SCMSecurityResponse handleError(SCMSecurityResponse resp)
      throws SCMSecurityException {
    if (resp.getStatus() != SCMSecurityProtocolProtos.Status.OK) {
      throw new SCMSecurityException(resp.getMessage(),
          SCMSecurityException.ErrorCode.values()[resp.getStatus().ordinal()]);
    }
    return resp;
  }

To solve this issue, one possible solution is on server check if it is SCMSecurityException with errorCode NOT_A_PRIMARY_SCM return a RetriableWithFailOverException. In this way, FailOverProxyProvider performs failOver and Retry to the next SCM.

The exception message is available in comments.