Let's perform some basic troubleshooting steps to fix this, joan of arc1.
It could be that the stored temporary internet files in your system are preventing your IOP account to sync with QBO. Let's start with accessing your IOP using a private window, this mode doesn't save your searches and site data. You can press Ctrl + Shift + N for Google Chrome or Ctrl + Shift + P for Mozilla Firefox and Internet Explorer. If it's now syncing, we'll have to go back to your regular and clear the cache to delete the junk files. If the same thing happens, we can use other supported browsers for the meantime so that you can get back to work. The one you're currently using may have a temporary issue with IOP.
If you'll still encounter the error after doing the steps above, I'd suggest calling our IOP technical support. This way, the can pull up your account and perform a screen-sharing session. Our specialist will gather data and conduct some tests on your account to fix the error.
You can refer to this link to contact support.
Feel comfortable to drop a post in the Community if you need additional assistance in doing your task with QuickBooks. It's always our pleasure to help. Happy New Year!
