Conversion failed when converting from a character string to uniqueidentifier Left Join

Question

I very rarely do SQL and am trying to do a left join on two tables in SSMS

Two databases and one has column ACT_HistoryID__c as type varchar(255) and the other database has a column HistoryID as PK uniqueidentifier

When I do:

SELECT H.[ActivityDate]
           ,H.ACT_HistoryID__c
           ,D.HISTORYID
           ,D.DURATION
FROM [Sales_Import].[dbo].[Task_History] as H
left join [National_MDB_26].[dbo].[HISTORY] as D
on H.ACT_HistoryID__c = D.HISTORYID

I get Msg 8169, Level 16, State 2, Line 2 Conversion failed when converting from a character string to uniqueidentifier

I have tried casting converting with no success although my limited understanding is that SQL should attempt the conversion itself.

I have ran the below SQL to check if there is a corrupt value and it returns all rows:

SELECT [ActivityDate]
FROM [Sales_Import].[dbo].[Task_History]
WHERE  TRY_CONVERT(UNIQUEIDENTIFIER, ACT_HistoryID__c) IS NOT NULL;

I have copied the ACT_HistoryID_c value and performed a lookup which returned a row

SELECT [HISTORYID]
      FROM [National_MDB_26].[dbo].[TBL_HISTORY]
      where HISTORYID = '5B437BBC-3D78-49F8-8365-59480A57410A'

I presume it's something stupid however any insights in where I.m failing?

CREATE TABLE [Task_History_V2] (
    [ActivityDate] varchar(255),
    [ACT_Attachment_Display__c] varchar(255),
    [ACT_Attachment_Filename__c] varchar(255),
    [ACT_Attachment_URL__c] varchar(255),
    [ACT_CreateDate] varchar(255),
    [ACT_EditDate] varchar(255),
    [ACT_GroupID__c] varchar(255),
    [ACT_HistoryID__c] varchar(255),
    [ACT_RecordMgr__c] varchar(255),
    [ACT_Type__c] varchar(255),
    [ACT_WhatID_Op__c] varchar(255),
    [ACT_WhatID__c] varchar(255),
    [ACT_WhoID__c] varchar(255),
    [CreatedByID] varchar(255),
    [CreatedDate] varchar(255),
    [Description] varchar(255),
    [LastModifiedByID] varchar(255),
    [LastModifiedDate] varchar(255),
    [Outlookid__c] varchar(255),
    [OwnerID] varchar(255),
    [Status] varchar(255),
    [Subject] varchar(255),
    [TasksubType] varchar(255),
    [X_Companies_Involved] varchar(255),
    [X_Company] varchar(255),
    [X_Contact] varchar(255),
    [X_Contacts_Involved] varchar(255),
    [X_Has_Multiples] varchar(255),
    [X_IsPrivate] varchar(255)
)

CREATE TABLE [dbo].[TBL_HISTORY](
    [HISTORYID] [uniqueidentifier] NOT NULL,
    [HISTORYTYPEID] [smallint] NOT NULL,
    [ISPRIVATE] [tinyint] NOT NULL,
    [STARTTIME] [smalldatetime] NOT NULL,
    [ENDTIME] [smalldatetime] NOT NULL,
    [REGARDING] [nvarchar](256) NULL,
    [DETAILS] [nvarchar](max) NULL,
    [ACCESSOR_ACTIVITY_CLEAREDID] [uniqueidentifier] NULL,
    [MANAGEUSERID] [uniqueidentifier] NOT NULL,
    [CREATEUSERID] [uniqueidentifier] NOT NULL,
    [CREATEDATE] [datetime] NOT NULL,
    [EDITUSERID] [uniqueidentifier] NULL,
    [EDITDATE] [datetime] NULL,
    [DURATION]  AS (datediff(minute,[STARTTIME],[ENDTIME])),
    [OUTLOOKID] [uniqueidentifier] NULL,
 CONSTRAINT [TBL_HISTORY_PK] PRIMARY KEY NONCLUSTERED 
(
    [HISTORYID] ASC
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON, OPTIMIZE_FOR_SEQUENTIAL_KEY = OFF) ON [PRIMARY]
) ON [PRIMARY] TEXTIMAGE_ON [PRIMARY]

Solution Not Answer I inserted the table to my Sales_Import database and converted the Guid to a string and my join then worked...