Hello @LSL ,
Welcome to community :)
Could you please check this article : https://support.atlassian.com/jira/kb/add-watchers-and-vote-buttons-are-greyed-out-in-team-managed-project-issues/
This has few reasons why the button is not available or greyed out.
Incase it doesnt solve the issues screenshots or error message would help here
Thank You,
Prachi
Hello @LSL
Welcome to the Atlassian community.
What happens when you try? Do you get an error message?
Can you provide screen images of what you see?
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