Why the issue cause Save button no working when did bank matching by added resolving transactions?

Good day, @fferl2020@gmail.

I'll help you fix the Save button so you can finish categorizing your downloaded banking transactions. 

Sometimes too much cache build-up in a browser can cause unexpected behavior with the product. This can be the reason why you're unable to save your progress. 

To isolate the issue, let's run some basic troubleshooting steps. To start, open your account in a private window. This will help us check if the issue is cache-related and fix it. Simply press the following shortcut keys to open this mode:

• Ctrl + Shift + N (Google Chrome).
• Ctrl + Shift + P (Firefox).
• Control + Option + P (Safari).

 
Once done, head back to the Banking page and try to categorise your bank transactions. If you're able to complete the process, go back to your regular browser and clear its cache. If you're still getting the same results, use another supported browser instead. 

Moreover, you can create bank rules to automatically categorise transactions from your bank. You can check out this article for your reference: Set up bank rules to categorise online banking transactions in QuickBooks Online.
 

If there's anything else I can do for you, please let me know. I'll be around to help you. Have a beautiful day!