Hi Jon-Paul,
Welcome to Microsoft Community.
I'm Hahn and I'm here to help you with your concern.
I’m sorry to hear that you are having trouble uploading documents online.
There could be several possible causes for this issue, such as network settings, browser settings, file permissions etc.
One possible solution is to reset your network settings and restart your computer. This might help resolve any network-related problems that prevent you from uploading files online.
Another possible solution is to check your browser settings and make sure that you have enabled JavaScript and cookies, disabled pop-up blockers, and cleared your browser cache and cookies. These steps might help improve your browser performance and compatibility with online sites.
Clear your browser cache and cookies. Sometimes, a buildup of cached files and cookies can cause issues with websites. Clearing them may help resolve the problem.
Check for updates. Make sure your operating system, browser, and any relevant software (such as Microsoft Office) are up to date with the latest updates and patches.
Disable browser extensions. Sometimes browser extensions can interfere with website functionality. Try disabling any extensions you have installed and see if that resolves the issue.
Run a virus scan. It's possible that your computer has been infected with malware that is interfering with file uploads. Run a virus scan to make sure your system is clean.
Use the Task Manager: Open the Task Manager by pressing the Ctrl + Shift + Esc keys. Look for any processes related to the browser or file uploader and end them. Then try uploading the file again.
Disable antivirus software temporarily: Sometimes, antivirus software can interfere with file uploads. Try disabling your antivirus software temporarily and see if that resolves the issue.
Check your file format: Make sure that the file you are trying to upload is in a compatible format. Some websites may only accept certain file types.
Disable firewall temporarily: If you have a firewall enabled, try disabling it temporarily to see if that resolves the issue.
Clear the DNS cache: Open the Command Prompt and type "ipconfig /flushdns" (without quotes) and hit Enter. This will clear the DNS cache and may resolve the issue.
Reset your browser settings: Try resetting your browser settings to their default state. This will remove any custom settings and may resolve the issue.
Hope the above information will be helpful to you. If there is anything not clear, please do not hesitate to let me know.
Your Sincerely
Hahn - MSFT | Microsoft Community Support Specialist