My users are getting this error "database not available" when attempting to access a solution (the only solution) on this server.  I get the error on a Macbook with Safari, they get the error with a PC using IE.

I notice when searching for this error that some solve it by redeploying the server, or rebooting the server, or removing the "spaces" in the name and replacing them with "_".  I've tried all that.  Still getting the error.  I'm not sure what else to try.

FMS 14.0.4.412 / WS 2012 R2

Did it used to work?

Do you get that error right off the bat?

Yes - immediately, however, the user can click OK and they are permitted into appropriate areas correctly based on their permissions.  It's odd.  I've tried to reproduce this error on my Mac and PC using Safari, IE, Chrome, FireFox and could only get it to occur once.  Then never again.  Some users get it more often, but not consistently.  

I administer over 125 solutions across 5 servers (14.0.4a) and have never encountered this before.

I would take a look at the log files inside the /Library/FileMaker Server/  folder and see if anything unusual shows up.

the problem comes from the file name   "****_****"  don't use underscores