Internal error when training custom category

I'm trying to use the Content Safety Studio to train the AI on a custom category. I uploaded my .jsonl file to a blob storage and have 64 examples in the following format in the file:

{"text": "Message: Temporary Access Token  One-Time Access Token Use this token to access the temporary file viewer. This token is valid for 1 hour only. xxxx Do not refresh the page after entering the code. ", "isPositive": true}
{"text": "Message: Access Token  One-Time Access Token Use this token to access the file viewer. This token is valid for 1 hour only. xxxx Do not refresh the page after entering the code. ", "isPositive": true}

Except every time I try to train the model, the training status fails with 'internal error'. I've tried five times now and I get the internal error every time. Are there certain restricted characters or something? The documentation here is severely lacking and it takes at least two hours for it to error out so it's incredibly difficult to troubleshoot.