I have an Angular app which calls a number of REST APIs from a Service written in Java using SpringBoot.

The first API is a "log in" API which results in an access token being returned in a cookie on the response.

All subsequent API calls need to include that access token in the request cookie.

When developing locally - ng serve on port 4200 and Spring Boot on port 8080, this all works fine.

On deploying to a test server - AWS S3 for the app, AWS Elastic Beanstalk for the service, I notice a problem *only in Safari for Mac and iOS*.

The initial login request is successful, and I get the access token cookie in the response.

However, subsequent requests from the browser do not include the cookie.

The cookie is not present when looking at Cookie Storage in the web console.

This only seems to affect Safari. It works absolutely fine in Firefox.

I notice that in Firefox, I see a warning about the SameSite attribute in the cookie being invalid or absent. I see no such warning or error in Safari. I don't this this is the problem, because this has not been a problem in Safari when accessing my development server.

Safari and Firefox both work when accessing my locally dev server.
Firefox works when accessing my test server on AWS.
Safari doesn't work when accessing my test server on AWS.

Both services are HTTP not HTTPS yet.

**Update**: I wrote this question in frustration about a week ago, and I realise it was badly described. I went to clean it up today, and in an attempt to add more specific info tried to access my test server again and Lo! and behold! it works. I have no idea what changed - I made no changes to client or server. I can only imagine it needed to "settle" somehow!