Is it possible to put up a brand new, very small, simple test file on your server and test the same behavior? If you get the same crash, that strongly suggests that the issue lies with the FileMaker software. If you do not, it's possible that there is an issue with this specific file.
You might also take a copy of the file down off the host machine and use Recover on it to check for issues with your file. Even if recover reports no problems, you might then upload that recovered copy to your server as a test to see if you get a crash.
Note 1: crashes can damage a file and file damage can cause a crash so it can be difficult to determine which is the cause and which is the effect.
Note 2: You may have this working beautifully via FileMaker Pro clients and only be getting crashes with the GO clients. This does not absolutely indicate that the file is OK. File damage in rare situations can manifest in crashing or other observable problems only with specific versions of the software or even versions of the OS--and this would also apply to FM GO vs. FM Pro differences in behavior.
Matt Petrowski has a filemakermagazine.com article about this in his Data Separation series (part 8). His solution is to have a generic login with no password on the UI (local) file, and a specific user account with appropriate access on the data file (on the server).