If it was AoE2, this support article should help:
If you still have the issue after the troubleshooting steps, view the note at bottom of that support page about submitting a request to the Support team.
For what it’s worth, one person a long time ago said they disabled firewall as the game launches and then enabled firewall when the Main Menu appears, and that was a workaround for them:
Searching the forum for 0xffffffff may yield other helpful results for you