I am a beginner to SF coding. I am getting this error  System.LimitException: Too many query rows: 50001 at line 17

my code is this, i am not sure why i am getting this error.

public class TransferTriggerHandler {
    public static final string COMMENT_TRUNCATED_MSG = Label.Comment_Truncated_Msg;
    public void OnAfterInsert(Transfer__c[] newTransObjects){
        
        
        List<Case> caseList = new List<Case>();
        List<CaseComment> caseCommentList = new List<CaseComment>();
        Map<id,Case> caseMap =  new Map<id,Case>([Select Id,Action_Owner__c,Action_Owner_Assignee__c,Minutes_Worked__c,accountId,account.ownerId from Case]); 
       
        boolean isPublish = false;
        String comment;
        
        for(Transfer__c trans: newTransObjects) {
            comment = 'New Transfer :'+trans.Name;
            comment += ' |Assigned Group:' + (trans.Action_Owner__c != null? trans.Action_Owner__c :' ') ;
            comment += ' |Summary of Issue:' + (trans.Summary_of_Issue__c != null ? trans.Summary_of_Issue__c : ' ');
            comment += ' |Customer Hardware Details:' + (trans.Customer_Hardware_Details__c != null ? trans.Customer_Hardware_Details__c : '') ;
            comment += ' |Work Done So Far:' + (trans.Work_Done_So_Far__c !=null ? trans.Work_Done_So_Far__c : '');
            comment += ' |Evidence/Supporting Details:' + (trans.Evidence_Supporting_Details__c !=null ? trans.Evidence_Supporting_Details__c : ''); 
            comment += ' |Expected Next Actions:' + (trans.Expected_next_actions__c != null ? trans.Expected_next_actions__c : '');
            comment += ' |Escalation Reason: ' + (trans.Escalation_Reason__c != null ? trans.Escalation_Reason__c : '');
            
            if (comment.length() > maxCommentLength) {
                //This comments is too long, we need to truncate it/
                comment =  comment.substring(0, maxCommentLength) + COMMENT_TRUNCATED_MSG;                    
            }
            
            Case c = caseMap.get(trans.case__c);
            CaseComment cc = new CaseComment(CommentBody= comment, IsPublished=isPublish,ParentId= c.id);
            caseCommentList.add(cc);
            insert caseCommentList;
           
            if(trans.Action_Owner__c =='Sales'){
           
                c.Action_Owner_Assignee__c = c.account.ownerid ;
                c.Action_Owner__c =trans.Action_Owner__c;
                c.Minutes_Worked__c= trans.Minutes_Worked__c;
            }
            else{
                c.Action_Owner_Assignee__c = null;
                c.Action_Owner__c =trans.Action_Owner__c;
                c.Minutes_Worked__c= trans.Minutes_Worked__c;
            }
            caseList.add(c);
        }
        try{
            if(caseList.size() > 0) {
                update caseList;
            }
        }  
        catch (Exception e){
            System.debug('Failed in transfer trigger handler class insertion'+e);
        }          
        
    }
    

    @TestVisible private static integer maxCommentLength {
        get
        {
            List<AddTransferFieldstoCase__c> tfc = AddTransferFieldstoCase__c.getall().values();
           
            integer returnValue = 4000;
           
            if (tfc.size() > 0) {
                returnValue = (integer)(tfc[0].MaxCommentLength__c);
            }

           
            returnValue = returnValue - COMMENT_TRUNCATED_MSG.length();

            if (returnValue < 0) throw new CommentConvertException('Maximum comment length is less than Zero. Check settings.');
            return returnValue;
        }
    }
    
    public class CommentConvertException extends Exception {}
}