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Thank you for reporting a bug to Unity. Our investigation indicates the issue originates from a third-party software, rather than Unity itself. Because the problem lies outside our codebase, we're unable to address it directly. We reported a bug to WebKit: https://bugs.webkit.org/show_bug.cgi?id=314551 We will close this case as a third-party issue. We recommend contacting the vendor or maintainer for support. If you have evidence that the issue is within Unity, please share it and we will re-open the investigation. We found that reducing the size of the WebAssembly file using build and code optimization settings allows to work around the bug. Please refer to https://docs.unity3d.com/Manual/web-setting-configurations.html and https://docs.unity3d.com/Manual/managed-code-stripping.html for more information.
Reproduction steps:
1. Open the attached “IN-135832” project
2. In Project Settings → Player Settings -> Publishing Settings -> WebAssembly Language Features, enable "Enable Native C/C++ Multithreading"
3. Build the Web Player
4. Install the “local-web-server” package
5. Open the terminal inside the build folder and run “ws --https --cors.opener-policy same-origin --cors.embedder-policy require-corp“ to host a build with the required headers
Actual result: The webpage reloads multiple times or infinitely, sometimes it shows a black screen saying “A problem repeatedly occurred on “https://ip:8000/”.
Expected result: The webpage loads successfully on the first attempt
Reproducible with: 2023.1.0a15, 6000.0.71f1, 6000.3.12f1, 6000.4.1f1, 6000.5.0b1, 6000.6.0a1
Testing environment: macOS 26.3.1
Reproducible with these devices:
VLNQA00634 - iPhone 15 Plus (MU0Y3QN/A), CPU: t8120, OS: 26.3
By reporter - iPhone XS, OS: 18.7.5
Not reproducible with these devices:
VLNQA00626 - iPhone 16 (MYE73QN/A), CPU: Apple A18 Pro, OS: 18.6.2 (Player always opens on first attempt)
Couldn’t test with these devices:
VLNQA00491 - iPhone 14 Pro (MQ083PX/A), CPU: Apple A16 Bionic, OS: 16.0 (says that Safari 16.0 does not support multithreading)
VLNQA00346 - iPad Air (4th generation) (MYFR2HC/A), CPU: Apple A14 Bionic, OS: 26.1 (Some JavaScript error shows, but Player opens)
Note: Reproducible with Safari, Chrome and Firefox
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