Azure Eventgrid new subscription create button grayed out

Question

the "Create" button keeps going gray when i try to create a new event subscription. There is no other feedback.

example subscription:

{
    "name": "MyQueueSubscription",
    "properties": {
        "topic": "/subscriptions/someSubBlah/resourceGroups/ImageAndThumbnail/providers/Microsoft.Storage/storageAccounts/mystorage01",
        "destination": {
            "endpointType": "StorageQueue",
            "properties": {
                "resourceId": "/subscriptions/someSubBlah/resourceGroups/ImageAndThumbnail/providers/Microsoft.Storage/storageAccounts/mystorage01",
                "queueName": "my-queue"
            }
        },
        "filter": {
            "includedEventTypes": [
                "Microsoft.Storage.BlobCreated"
            ],
            "advancedFilters": [
                {
                    "operatorType": "StringBeginsWith",
                    "key": "subject",
                    "values": [
                        "/blobServices/default/containers/my-container"
                    ]
                },
                {
                    "operatorType": "StringEndsWith",
                    "key": "subject",
                    "values": [
                        ".ai",
                        ".pdf"
                    ]
                }
            ],
            "enableAdvancedFilteringOnArrays": true
        },
        "labels": [],
        "eventDeliverySchema": "EventGridSchema",
        "retryPolicy": {
            "maxDeliveryAttempts": 10,
            "eventTimeToLiveInMinutes": 120
        },
        "deadLetterDestination": {
            "endpointType": "StorageBlob",
            "properties": {
                "resourceId": "/subscriptions/somesubblah/resourceGroups/ImageAndThumbnail/providers/Microsoft.Storage/storageAccounts/mystorage01",
                "blobContainerName": "dead-letter-storage"
            }
        }
    }
}

What am i doing wrong/why does this not work?

Answer 1

@Finlay, Matthew You may try with IE 11 or Edge Version 89.0.774.45 (Official build) (64-bit). Yes CLI or PowerShell is another option. However, you can directly create event grid subscription under the event grid subscription service as mentioned here :
https://stackoverflow.com/questions/66481745/azure-portal-wont-let-me-create-a-subscription-to-an-azure-event-grid-topic-cr

Please "Accept the answer" or "up-vote" if this helps.