Hello,
I have been running SME as my firewall / gateway for years (currently 7.4). I have just changed ISP and reconfigured the server (it is in server/gateway mode) for the WAN connection. It was PPoE and with the new ISP it was changed to static IP.
After reconfiguring .... until I can reconfigure it.
Maybe you could clarify this better. You imply that you have reconfigured it and yet you say "until I can reconfigure it". That is contradictory.
What Charlie is suggesting is that if you went through the normal "configure this server" panels in server console changing the PPoE connection to a static IP AND you can not boot up then that is a bug as the system does not work that way. I have changed modes from PPoE to Static on the same server several times without problem. IF that is what you mean, then raise a bug report, you will get better help.
Remember, raising a bug report is NOT accusing the program that it doesn't work, it is a method of tracking problem issues better than these forums. Don't be shy.
By the way, if the server can't find the device after rebooting several times, it may be a hardware failure.