Redshift Serverless Timeout

We've been using AWS Redshift Serverless for a while (whilst it was in preview) with no issues. We've just added a new IAM user for one of our team to access Redshift for data analytics. The account has the exact same permissions as all other accounts with Redshift access. For some reason, when they try use the Query editor to access the DB they get this error:

Databases couldn't be listed.
Connection is not available, request timed out [ErrorId: 1-62e7d16e-2e1f6bb7012371163e34e2fe]

Other users have seen this temporarily in the past week, however after a refresh the error eventually goes away. However for this user no matter what they do they still see the error when opening the editor, blocking them from connecting. They have tried on multiple devices, as well as resetting browser cache & cookies, with no luck. They are in a different geographical location to most of the team, although this means they are actually closer to the AWS region we are using.

The Redshift Serverless instance is in a VPC, with the port 5439 open for all sources. This rule allows everyone else in the team to access the DB with no issues, so I don't think the firewall rules are the issue.

Has anyone seen this error before? Really odd its temperamental and does not affect all users. Thanks