Your ROOT_URL in app.ini is https://source.parasitstudio.de:63000/ but you are visiting https://source.parasitstudio.de/wirtz/esp-link/src/commit/7d6206f2d08c3ee5e04ea37f88425eb4e4f66cae/mqtt You should set ROOT_URL correctly, otherwise the web may not work correctly.

Thorsten von Eicken ef6a611045 Reduce memory consumption; fix syslog alloc when disabled		9 years ago
..
mqtt.c	Change MQTT hostname to 64 chars, fixes #147 An error occurred	9 years ago
mqtt.h	fix mqtt for new slip protocol	9 years ago
mqtt_cmd.c	Reduce memory consumption; fix syslog alloc when disabled	9 years ago
mqtt_cmd.h	new SLIP protocol; basic REST working	9 years ago
mqtt_msg.c	massive rework of MQTT	10 years ago
mqtt_msg.h	Merge branch 'master' into windows	10 years ago
pktbuf.c	Fix for services page syslog filter select list	9 years ago
pktbuf.h	lots of ifdef	10 years ago