I have the same problem.
User agent: Mozilla/5.0 (X11; Linux x86_64; rv:134.0) Gecko/20100101 Firefox/134.0
Using Firefox on Arch Linux, installed from the normal Arch repos.
I think this is caused by Uncaught DOMException: The operation is insecure.
which can be seen in the console.
When searching fails, I see this:
Too many calls to Location or History APIs within a short timeframe. search:293:24380
Uncaught DOMException: The operation is insecure.
onsubmit https://kagi.com/search?q=testing two:293
EventHandlerNonNull* https://kagi.com/search?q=testing two:293
EventListener.handleEvent* https://kagi.com/search?q=testing two:293
search:293
When I click on an image in the image search results and it does not load, I see this:
Uncaught DOMException: The operation is insecure.
onclick https://kagi.com/asset/v1/js/k_ima.min.js?v=c8dda5c831e57e322ba05aa121fa11d497dd2a9d:1
initImagePreview https://kagi.com/asset/v1/js/k_ima.min.js?v=c8dda5c831e57e322ba05aa121fa11d497dd2a9d:1
renderImagesPage https://kagi.com/asset/v1/js/k_ima.min.js?v=c8dda5c831e57e322ba05aa121fa11d497dd2a9d:1
<anonymous> https://kagi.com/asset/v1/js/k_ima.min.js?v=c8dda5c831e57e322ba05aa121fa11d497dd2a9d:1
onSocketMessage https://kagi.com/images?q=testing:356
onSocketMessage https://kagi.com/images?q=testing:356
connect https://kagi.com/images?q=testing:356
onsubmit https://kagi.com/images?q=testing:356
EventHandlerNonNull* https://kagi.com/images?q=testing:356
EventListener.handleEvent* https://kagi.com/images?q=testing:356
k_ima.min.js:1
onclick https://kagi.com/asset/v1/js/k_ima.min.js?v=c8dda5c831e57e322ba05aa121fa11d497dd2a9d:1
(Async: EventHandlerNonNull)
initImagePreview https://kagi.com/asset/v1/js/k_ima.min.js?v=c8dda5c831e57e322ba05aa121fa11d497dd2a9d:1
renderImagesPage https://kagi.com/asset/v1/js/k_ima.min.js?v=c8dda5c831e57e322ba05aa121fa11d497dd2a9d:1
<anonymous> https://kagi.com/asset/v1/js/k_ima.min.js?v=c8dda5c831e57e322ba05aa121fa11d497dd2a9d:1
onSocketMessage https://kagi.com/images?q=testing:356
forEach self-hosted:157
onSocketMessage https://kagi.com/images?q=testing:356
(Async: EventHandlerNonNull)
connect https://kagi.com/images?q=testing:356
onsubmit https://kagi.com/images?q=testing:356
(Async: EventHandlerNonNull)
<anonymous> https://kagi.com/images?q=testing:356
(Async: EventListener.handleEvent)
<anonymous> https://kagi.com/images?q=testing:356
Happy to help diagnose, let me know if you need any further information or testing.