See if your account is eligible to set up payments per https://support.google.com/adsense/answer/1709858?hl=en
If not, then wait until it is.
If you are eligible or are having problems adding /changing payments info, then Adsense is aware of this issue and working on it.
Try using a different web browser, and temporarily disabling all extensions and add-ons.
You can send feedback from your account and wait for it to be fixed.
Sorry, we don’t know when this will be fixed.