After updating the HA Core, ESPHome Builder no longer works and continues to display the message:
The HA versions are:
Post your yaml code (formatted) and compiler log.
I experience the same for the last few weeks. Looks like the CPU goes to 100% for a long time, and makes HA OS to reboot. I’m running HA OS on a fairly powerful Lenovo Thinkcentre i5 7500 with 16GB of ram.
I expect some load balancing challenges introduced in one of the last updates not leaving a minimum of CPU to HA Core.
This is definitely a problem. I am experiencing the same issue.
The sound of wind blowing through the tumbleweeds. No info, no help.
LMAO! Not my first rodeo here. What YAML code? What compiler log?
We are not experiencing device failure here, we are experiencing an ESPHome Builder failure. Nothing in the logs, nothing in the changelogs, nothing suggesting a breaking change. The only evidence it is even occurring is this:
2026-01-04 13:31:04,699 WARNING 403 GET /events (0.0.0.0) 1.04ms
2026-01-04 13:31:05,754 WARNING 403 GET /events (0.0.0.0) 1.28ms
2026-01-04 13:31:06,818 WARNING 403 GET /events (0.0.0.0) 1.12ms
2026-01-04 13:31:07,871 WARNING 403 GET /events (0.0.0.0) 1.11ms
2026-01-04 13:31:08,919 WARNING 403 GET /events (0.0.0.0) 1.04ms
2026-01-04 13:31:09,960 WARNING 403 GET /events (0.0.0.0) 0.54ms
2026-01-04 13:31:11,008 WARNING 403 GET /events (0.0.0.0) 1.07ms
2026-01-04 13:31:12,068 WARNING 403 GET /events (0.0.0.0) 5.03ms
2026-01-04 13:31:13,137 WARNING 403 GET /events (0.0.0.0) 1.09ms
2026-01-04 13:31:14,195 WARNING 403 GET /events (0.0.0.0) 1.04ms
2026-01-04 13:31:15,251 WARNING 403 GET /events (0.0.0.0) 3.26ms
2026-01-04 13:31:16,314 WARNING 403 GET /events (0.0.0.0) 2.22ms
The manifestation is a blank ESPHome Builder dashboard with the rotating “Connection Lost. Reconnecting…” and then “Connection restored.” Over and over.
I’m working the problem but I suspect that it is only affecting those with some form of reverse proxy coupled with local SSL certs. If it was widespread, the world would be on fire.
Are you guys running SSL certs locally on HA? Also, do you have a reverse proxy in place?
My theory that it was an authentication issue brought about by a change in ESPHome Builder 2025.12.3 seems valid to some degree; I removed HA SSL and reverted to Caddy forwarding plain HTTP to HA and the problem is resolved.
This definitely came in with 2025.12.3 and isn’t (obviously) listed as a breaking change.
Even the fact you cannot get to that is of some help