Re: Access Services is unable to process the request.

Hello HEN,

I would like to confirm the following things:
1.The SharePoint Online Access Database was published from Access 2010 locally to your SharePoint Online by using Publish to Access Services.
2.What do you mean by saying “re-upload it”?

After you open the Access database in Access 2010 which is associated with an Access Services website, when you click File, Info, Click Sync All, it will be synced to SharePoint Online.

If the issue persists, you can run Office desktop by following this link: Set up your desktop for Office 365

Thanks,
Cherry Wang