Why am I getting this error (error is on the bold line of code below)-- 
System.CalloutException: You have uncommitted work pending. Please commit or rollback before calling out

public  class S3Controller {
    
    public static void UploadDocToS3Server(string recordId)
    {
        UploadDocument(recordId);
    }
    
    @future(callout=true)
    public static void UploadDocument(string recordId)
    {
        //S3 Key 
        String key = '123'; 
        //S3 Secret Key 
        String secret = '123/123/123';
        String bucket = '123'; 
        String host = 's3-us-east-1.amazonaws.com';
        String method = 'PUT';
        ProfilityCallout service=new ProfilityCallout(key,secret,bucket,method,host);
            ProfilityCallout.UploadDocuments(recordId,key,secret,bucket,method,host);
    
    }

}

public class ProfilityCallout {
 
   
    public  string awsKey {get;set;}
    public   string awsSecret {get;set;}
    public   string bucketName {get;set;}
    public   string methodName {get;set;}
    public static  string hostName {get;set;}
    public  static string statusCode {get;set;}
    public static string bucketNameStatic {get;set;}
    public static string methodNameStatic {get;set;}
    public static string hostNameStatic {get;set;}
    
    public static string awsKeyStatic {get;set;}
    public  static string awsSecretStatic {get;set;}
    
    public  ProfilityCallout(string key, string secret, string bucket, string method, string host){
        awsKey=key;
        awsSecret=secret;
        bucketName=bucket;
        methodName=method;
        hostName=host;
        bucketNameStatic = bucket;
        methodNameStatic = method;
        hostNameStatic = host;
    }
    
    public  string ContentType(string fileType) {
        switch on fileType.toLowerCase()
        {
            when 'docx'
            {
                return 'application/vnd.openxmlformats-officedocument.wordprocessingml.document';
            }
            when 'csv'
            {
                return 'application/vnd.ms-excel';
            }
            when 'wav'
            { 
                return 'audio/wav';
            }
            when 'wmv'
            {
                return 'video/x-ms-wmv';
            }
            when 'mp3'
            {
                return 'audio/mpeg';
            }
            when 'mp4'
            {
                return 'video/mp4';
            }
            when 'png'
            {
                return 'image/png';
                
            }
            when 'pdf'
            {
                return 'application/pdf';
                
            }
            when else {
                return 'image/jpeg';
            }
        }
    }
    
    public  string CreateAuthHeader(String contentType,
                                   String filename, String formattedDateString,string fileExtension){
                                       string auth;
                                       String stringToSign = this.methodName+'\n\n'+contentType+'\n'+formattedDateString+'\n/'+this.bucketName+'/'+filename.toLowerCase()+ '.'+fileExtension.toLowerCase();
                                       Blob mac = Crypto.generateMac('HMACSHA1', blob.valueof(stringToSign),blob.valueof(this.awsSecret));
                                       String sig = EncodingUtil.base64Encode(mac);
                                       auth = 'AWS' + ' ' + this.awsKey + ':' + sig;
                                       return auth;
                                   }
    
  //  @future(callout=true)
    public static void UploadDocuments(string recordId,string key, string secret, string bucket, string method, string host){
        
        bucketNameStatic = bucket;
        methodNameStatic = method;
        hostNameStatic = host;
        awsKeyStatic=key;
        awsSecretStatic=secret;
            
      //  if(awsSecret.isBlank(this.awsSecret) || string.isBlank(this.awsKey) || string.isBlank(this.bucketName) || string.isBlank(this.hostName))
      //  {
         //   throw new BaseException('Set AWS credential');
      //  }
        List<ContentDocumentLink> links=[SELECT ContentDocumentId,LinkedEntityId FROM ContentDocumentLink where LinkedEntityId=:recordId];
        Set<Id> ids=new Set<Id>();
        for(ContentDocumentLink link:links)
        {
            ids.add(link.ContentDocumentId);
        }
        List<ContentVersion> versions=[SELECT VersionData,Title,ContentDocumentId,FileExtension FROM ContentVersion WHERE ContentDocumentId = :ids AND IsLatest = true];
        
        for(ContentVersion attach:versions) {
         //   try
         //   {
                //File Content
                String attachmentBody = EncodingUtil.base64Encode(attach.VersionData);
                String formattedDateString = Datetime.now().formatGMT('EEE, dd MMM yyyy HH:mm:ss z');
                
                String filename = attach.Title;
       //////FIX LATER         string contentType=ContentType(attach.FileExtension);
         /////       system.debug('contentType:'+contentType);
                
                string fileUrl='https://' + bucketNameStatic + '.' + hostNameStatic + '/' + filename.toLowerCase().remove(' ')+ '.'+attach.FileExtension.toLowerCase();
                HttpRequest req = new HttpRequest();
                req.setMethod(methodNameStatic);
                req.setEndpoint('callout:Seek/'+ filename.toLowerCase()+ '.'+attach.FileExtension.toLowerCase());
                req.setHeader('Host', bucketNameStatic + '.' + hostNameStatic);
                req.setHeader('Content-Length', String.valueOf(attachmentBody.length()));
                req.setHeader('Content-Encoding', 'UTF-8');
         /////       req.setHeader('Content-type', contentType);
                req.setHeader('Connection', 'keep-alive');
                req.setHeader('Date', formattedDateString);
                req.setHeader('ACL', 'public-read');
                Blob pdfBlob = EncodingUtil.base64Decode(attachmentBody);
                req.setBodyAsBlob(pdfBlob);
                   
       //////FIX LATER          req.setHeader('Authorization',CreateAuthHeader(contentType, filename, formattedDateString,attach.FileExtension));
                
                Http http = new Http();
                HTTPResponse res = http.send(req);
               statusCode = string.valueof(res.getStatusCode());
                if (res.getStatusCode() == 200 || res.getStatusCode()==201) {
                     Messaging.SingleEmailMessage message = new Messaging.SingleEmailMessage();
                        message.setSubject('Profility S3 PUT succesful!');
                        message.setPlainTextBody('Profility S3 PUT succesful!');
                        message.setToAddresses( new String[] { '123@123.org' } );
                        Messaging.sendEmail( new Messaging.SingleEmailMessage[] { message } ); 
                 
                }
            
         //   catch(Exception ex)
         else   {
                
                     Messaging.SingleEmailMessage message2 = new Messaging.SingleEmailMessage();
                        message2.setSubject('issue with Profility callout');
                        message2.setPlainTextBody('issue with Profility callout '+statusCode );
                        message2.setToAddresses( new String[] { '123@123.org' } );
                        Messaging.sendEmail( new Messaging.SingleEmailMessage[] { message2 } ); 
            //   throw new BaseException(ex);
            }
        }
    }
}

Hi All.

Could you please help us to find a solution for our issue?

We need to set a custom URL for our SF Community (not a Force.com site). To do that we performed the following steps:
- registered a custom domain (www.mycompany.com) using the GoDaddy service and added a necessary CNAME there to point this URL to our SF community.
- added a domain for this URL in Salesforce.
- created a Custom URL in Salesforce to point this domain to the community.

Now, if we enter a custom URL in a browser (www.mycompany.com), then it correctly redirects us to the Salesforce community. And it's exactly what we want, except one thing: in address bar of a browser we still see old URL: XXX.force.com.

So, Is it possible to configure this custom URL so that we could see "www.mycompany.com" in an address bar? What should we pay attention for to implement this behavior?

Thank you. Gennadiy.

p.s. One of our assumptions is that we should do something more with CA-certificate and SSL-certificate. If anyone knows more whether they affect on the described problem or not, please push us in a right direction.