Frequently asked questions
NiimBlue does not use any hacks to bypass paper restrictions. It is not possible without firmware/tag modifications.
You still need a valid RFID tag to print.
In addition, the printer also stores the tag data in internal memory (something around 10 tags), so you can't trick the printer by removing the tag after reading it and printing without increasing the counter (unless you have old model). The tag data will be written to the tag the next time it is read.
Before creating an Issue, try to print with original app. Maybe the problem is not NiimBlue.
NiimBlue tries to support a wide range of models, but not all may be compatible. In order to add support for your model, you will need to do a packet dump of a successful print (see relevant Wiki page).
You can see the red line on your canvas. Roughly speaking, this is the position of the printer's print head relative to the label.
Solution:
Press "Fetch fonts" button (visible if your browser supports this feature). List will be filled with system fonts.
Font list will be cached to browser localStorage.
You can also provide own list by setting "font_cache" variable (F12 DevTools panel).
Example: ["Arial","Noto Sans Variable","Calibri"]
Looks like your browser has some permission problems.
Try to enable Experimental Web Platform Features or Web Bluetooth (navigate to chrome://flags).
For Vivaldi 7.x you need to install NiimBlue as app (right click on the NiimBlue tab - Install NiimBlue). Desktop shortcut will be created.
It was reported that this was happening with some USB cables. Try a different cable/hub.