URL Redirection to Untrusted Site

I have below code in service.ts file and VeraCode code scan fails

Flaws by CWE ID: URL Redirection to Untrusted Site ('Open Redirect') (CWE ID 601)(16 flaws) Description A web application accepts a untrusted input that specifies a link to an external site, and uses that link to generate a redirect. This enables phishing attacks.

Please help me to fix this

Service.ts:

public exportReviews(searchReviewData: SurveillanceReviewSearchViewModel): Observable<SurveillanceReviewSearchViewModel> {
    this._urlSurveillanceDetails = this.baseHref +"/ReviewProfile/ExportReviews";
    const headers: HttpHeaders = new HttpHeaders();
    headers.append('Content-Type', 'application/json');
    return this.http.post<SurveillanceReviewSearchViewModel>(this._urlSurveillanceDetails, searchReviewData, { headers: headers }); // flaw identified on this line
  }

public getReviewsBySearchSessionId(searchsessionId): Observable<SurveillanceReviewSearchViewModel> {
    this._urlSurveillanceDetails = this.baseHref + "/ReviewProfile/SearchReviewsBySessionId" + '?searchsessionId=' + searchsessionId;
    var headers = new HttpHeaders();
    headers.append('Content-Type', 'application/json');
    this._urlSurveillanceDetails = this.sanitizer.sanitize(SecurityContext.RESOURCE_URL, this.sanitizer.bypassSecurityTrustResourceUrl(this._urlSurveillanceDetails));
    return this.http.post<SurveillanceReviewSearchViewModel>(this._urlSurveillanceDetails, headers); // flaw identified on this line
  }