I can't collect XMP while walking. I am standing on top of it but can't collect it. Any solution to that?
This happens when your connection to the servers is slow/failing.
When Ingress knows you have no network connection (the red notification top-right) it will pretend to scoop up xm; when it thinks you have a working connection it will only scoop up xm on your screen once it has had confirmation back from the server that the xm has been collected and logged against your account.