How to get a hyperlink in the Post Body in Salesforce without using LInkURL? [duplicate]

Question

As I am using this code to add a feeditem in the case. As it created a feeditem on the case but hyperLink is not working. In the documentation we got that isRichText supports the tag but in my salesforce org it is not able to generate the hyperlink on the Manas. It means that the text "Manas" appears, but is not clickable

Below is the Code that I used to create the feeditem.

FeedItem fd = new FeedItem();
fd.parentid = '5001w00000835Qk'; //any parent Id 
fd.body = '<a href = "https://d1w0000008iszeai--developer.my.salesforce.com/5001w0000081sOsAAI">Manas</a>'
fd.title = 'test';
fd.isRichText = True;
insert fd;