Hi,
NAT is compatible with standard SKU public IP, public IP prefix, and load balancer resources. Basic resources (for example basic load balancer) and any products derived from them aren't compatible with NAT. Basic resources must be placed on a subnet not configured with NAT.
A NAT gateway is compatible with the following:
- Standard load balancer
- Standard public IP
- Standard public IP prefix
As per the error message you are using a Basic Public IP address or Basic Load Balancer.
Reference:
https://learn.microsoft.com/en-us/azure/virtual-network/nat-gateway-resource#limitations
(Please don't forget to accept helpful replies as answer)
Best regards,
Leon