RTK not working (only 3D fix)

I have been trying to setup a here3 base and here3 gps to get RTK working. I followed the tutorial (except for the very last step with the u-center because none of my friends could get it working) but we can only get the message “GPS: 3D Fix” on the side. It was working a couple of months ago without doing the last step… I will try to get the last step working but in the meantime, has anyone had this problem before or know what it might be?

How was the environment?
Did you use mp or QGC ?
What accuracy did you set on your RTK base?
How long have you been wait for the RTK into the set accuracy?

I believe we were using mission planner
We first tested outside (however there were some 3-4 story buildings around us) and then moved indoors after it started raining. My friends tried to get it to work outside with about 2m accuracy but they couldn’t get it to work. We then moved inside to a windo and then to a balcony and set the accuracy to 15m.

It reached 2m and 15m within a couple minutes?

I tested it with a very wide accuracy (15m) because I thought the isssue was with the GPS or something. Does RTK only work with very precise accuracy (2m ish)?

The reason I didn’t think accuracy/environment would matter that much is because my friend said RTK was working a couple months before indoors. Not sure what accuracy he set it to, it was likely 2m or higher.