I can't add someone to a Facebook page. I go through the process to add them and nothing happens.

Is this a common problem? I have access to the page, but it hasn't been managed for a while. The company lacks access, but I have been granted permission to manage the ads. I tried to add someone with a Facebook page to give them access. I am asked for my Facebook password and then sent an email to confirm. However, it does not complete the process, and I am sent back to enter my password again.
I have tried on my desktop and through the facebook app but have the same issue. I have been trying this for weeks.

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