Hello Mubarish Ahmed A
Welcome to Microsoft Q&A Platform, thanks for posting your query here.
Based on the details shared, the error message shows that the Local administrator credentials entered in the Portal is not valid to access the cluster node. Please check if this local user is created on that node. Please also ensure the Domain Account entered in the Portal is also valid. If both are valid and matching with the AD user and Local user on the node then you should not see this error.
Hope this helps.