Compile Error: Variable does not exist: atm at line 52 column 32

it's hitting on the line atms.add(atm); but I just declared the atm the line before - please assist! I must be missing something obvious? Thanks!

trigger UserActivatedTeamCoverage on User (after insert, after update) {

    //when a user is activated or inserted, the should be added to the AccountTeams of Accounts they cover via TeamMember
    
    
    // declare some lists
    
    List < EntitySubscription > esSet = new List < EntitySubscription > ();
    List < AccountTeamMember > atms = new List < AccountTeamMember > ();
    List <coverage_Person__c> CPS = new List <Coverage_Person__c> ();
    List < Double > empIds = new List < Double > ();
    List < ID > UserID = new List < ID > ();
    List < AccountShare > ASSES = new List < AccountShare > ();
   
   //add info from the users to the lists for users who are active and have an EMP_id (all should!)
   
    For (User u1:trigger.new){
        if(u1.isActive=true) if (u1.EMP_id__c !=null)
        empIds.add(u1.Emp_Id__c);
        UserID.add(u1.id);
   }
   
   //get a list of team memberships for this person
   
   List <Coverage_Person__c> CP3 = [select name, id, emp_id__c, Coverage_Team__c  from Coverage_Person__c where emp_id__c IN: empIds];
   system.debug('CP3 the list of coverages=========================='+cp3);
   
   //add the teams to a list
    List <id> CP3Teams   = new List <ID>();
    for(Coverage_person__c es:cp3){CP3Teams.add(es.Coverage_Team__c);}
   system.debug('CP3Teams=======================the teams ids'+CP3Teams);
   
   
   //get the assigned teams of these Teams
   
   List <Assigned_Team__c> Assignments = [select name, id, emp_id__c, Account__c from Assigned_Team__c where Coverage_team__c IN: CP3Teams or EMP_id__c IN: empIds];
   system.debug('assignments========assigned teams========'+Assignments);
   
   //add the ids of the accounts from the AssTeams to a list
   List <id> AssignmentsAccounts = new List <id>();
   for (Assigned_Team__c os:Assignments){AssignmentsAccounts.add(os.Account__c);}
   system.debug('Assignments Accounts ids ======================= '+AssignmentsAccounts);
   
   //loop through User and find the link to the account, then create an accountTeamMember record for them
   
      For (User u1:Trigger.new){
          For (Coverage_Person__c C:CP3){
              if(c.User__c==u1.id)
                  For (Assigned_Team__c at:Assignments){
                      if(at.Coverage_Team__c==c.Coverage_Team__c)
                      AccountTeamMember atm = new AccountTeamMember (AccountID=at.Account__c, UserId=u1.id, TeamMemberRole='Coverage');
                      atms.add(atm);
                   }
                }
           }
    insert atms;
}