401 - Unauthorized: Access is denied due to invalid credentials

I got this gadget error on all project home page:
401 - Unauthorized: Access is denied due to invalid credentials.
You do not have permission to view this directory or page using the credentials that you supplied.
How to fix this problem? I have tried everything to fix but nothing works.

Hi @BenjaminYu. Just a few questions. Are you on Jira Server/DC or Cloud? Which gadget installed on your dashboard is throwing this error? Is this one you created yourself or was it created by a third-party?

Jira server software on Linux server with IIS web server. jira activity gadget causes this error.

We are using jira 8.13 server.