How to resolve this error, i want to load chat from mysql database
ERROR DOMException: Failed to execute ‘open’ on ‘XMLHttpRequest’: Invalid URL
at http://localhost:4200/polyfills.js:2222:25
at proto. [as open] (http://localhost:4200/polyfills.js:782:16)

url = ‘http://localhost:8080’;

loadChat(){
this.messages = this.http.post<Array>(this.url+’/getMessages’ , this.roomName);
this.messages.subscribe(data => {
let mgs:Array = data;
mgs.sort((a, b) => (a.ms_id > b.ms_id) ? 1 : -1)
this.messages = of(mgs);
})
console.log(this.messages);
}

chats are saved in database but i can’t get i got this error
get,post methods are tried