Mock LocationI cannot add a device — the limit is reached
Your account already has the maximum number of devices for your plan. Revoke a device you no longer need in your account — the freed slot immediately lets you connect a new one.
Most often the limit is taken by old installations: a reinstalled app or a phone you no longer use. The device list shows when each one last connected — that makes it easy to see which one to revoke.
The other option is to switch to a plan with more devices; the comparison is on the Premium page.