Thank you so much for your response.

Submitted an issue for this: https://github.com/NodeBB/NodeBB/issues/7601

Thank you so much for your answer @baris .

The issue was resolved when I removed the extra / in url in config.json

so from

{
"url": "https://forum.forum.com/",
...
}

to

{
"url": "https://forum.forum.com",
...
}