If you are referring to Bring Your Own Client link that was sent to you via email, then you need to send it to your client and follow the instructions in the email to notify Upwork about your contract with them.
Can your try clearing your cache and cookies and with another browser. If this does not work let me know what type of browser you used and i will escalate it further.
It's not to do with the browser.
I would like to invite a new client using the personal invitation link that gives 0% fees. I havn't been emailed a link yet, so can you email me my personal link?