UPDATE: Before reading the rest: could you double check that the file is not empty? Something about the error seems slightly off. If it has contents, then proceed. With errors such as this, it can be difficult to diagnose.
Are you working on a local Galaxy or the public Main Galaxy instance at http://usegalaxy.org? Or another public instance? Or cloud instance?
From the initial error it appears that the dataset you are attempting to visualize exceeds the memory available to the Galaxy instance you are working on. A "per dataset" indexing problem.
If on a local, moving to a cloud with more memory will almost certainly help. If on a cloud, allocate more memory. If working on another public Galaxy or Main, then moving to a Cloud is one potential solution to try.
With any of these, although perhaps excluding a local (on a laptop or similar), if the dataset you are trying to visualize is a composite (merge) of other datasets, you could try visualizing the components individually, but still in the same browser. No guarantees that this will work, but it is possible to drag tracks around within Trackster to group them into composite tracks after loading, to help organize the data that way, as an alternative.
Hopefully one of these options will help to solve the issue! But after trying the above, and you are on http://usegalaxy.org, or can reproduce the issue there, you can share a history with us at email@example.com and we can confirm the size issue.
Best, Jen, Galaxy team