If you are on Cloud and you're still running into this issue try the JIRA App from the App store and see if you're able to login. If this is server, does this work in another browser,e.g. Chrome, Firefox?
I would also check to make sure the JIRA Mobile module is enabled:
Hi my Community friends! For those who don't know me, I'm a product marketer on the Confluence Cloud team - nice to meet you! For those of you who do, you know that I've been all up in your Co...
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