A single AnyDesk license (depending on the tier) can be used on up to three devices concurrently for the same user. To add another device:

If you encounter issues during the activation process, it's recommended to contact AnyDesk support directly. They can provide specific guidance tailored to your situation, including any direct links or procedures they may have for activation or troubleshooting.

error may occur if a different license is already active in the client. AnyDesk Help Center whitelisting AnyDesk in your firewall? Register your license - AnyDesk Help Center