AWS Status page[1] shows a couple of issues in eu-west-2.

Amazon Elastic Compute Cloud (London)

Instance Connectivity

3:21 AM PDT We are investigating instance connectivity issues in a single Availability Zone (euw2-az2) in the EU-WEST-2 Region.

Amazon Relational Database Service (London)

Small number of instances unavailable in a single Availability Zone

3:36 AM PDT We are investigating connectivity issues affecting some instances in a single Availability Zone (euw2-az2) in the EU-WEST-2 Region.

[1] https://status.aws.amazon.com/