Firstly, have you encountered any error prompts or messages as you try to send the forms? While waiting for your response I would suggest to perform initial browser troubleshooting to isolate and fix common problems. Let me guide you with this.
Begin by logging into your QBO using an incognito window. This type of window doesn't rely on existing cache files, which helps us find out if the problem is related to the browser. Depending on the browser you're using, you can open a private window with one of the following keyboard shortcuts: