I have the same internal server error issue with iRedAdmin on Rocky Linux 8.6 with 1.6.2. Here is some info from my messages log. Hope this helps.
Nov 8 03:18:11 mx1 systemd[1]: iredapd.service: Control process exited, code=exited status=1
Nov 8 03:18:11 mx1 systemd[1]: iredapd.service: Failed with result 'exit-code'.
Nov 8 13:39:40 mx1 iredadmin[1065]: Traceback (most recent call last):
Nov 8 13:39:40 mx1 iredadmin[1065]: File "/opt/www/iRedAdmin-1.8.1/iredadmin.py", line 8, in <module>
Nov 8 13:39:40 mx1 iredadmin[1065]: from libs import iredbase
Nov 8 13:39:40 mx1 iredadmin[1065]: File "/opt/www/iRedAdmin-1.8.1/libs/iredbase.py", line 5, in <module>
Nov 8 13:39:40 mx1 iredadmin[1065]: import web
Nov 8 13:39:40 mx1 iredadmin[1065]: ModuleNotFoundError: No module named 'web'
Nov 8 13:39:40 mx1 iredadmin[1065]: unable to load app 0 (mountpoint='192.168.0.171|/iredadmin') (callable not found or import error)
Nov 8 13:39:40 mx1 iredadmin[1065]: --- no python application found, check your startup logs for errors ---
Nov 8 13:39:40 mx1 iredadmin[1065]: [192.168.0.249] GET /iredadmin 500 104 "-"
Nov 8 13:39:49 mx1 iredadmin[1065]: Traceback (most recent call last):
Nov 8 13:39:49 mx1 iredadmin[1065]: File "/opt/www/iRedAdmin-1.8.1/iredadmin.py", line 8, in <module>
Nov 8 13:39:49 mx1 iredadmin[1065]: from libs import iredbase
Nov 8 13:39:49 mx1 iredadmin[1065]: File "/opt/www/iRedAdmin-1.8.1/libs/iredbase.py", line 5, in <module>
Nov 8 13:39:49 mx1 iredadmin[1065]: import web
Nov 8 13:39:49 mx1 iredadmin[1065]: ModuleNotFoundError: No module named 'web'
Nov 8 13:39:49 mx1 iredadmin[1065]: unable to load app 0 (mountpoint='192.168.0.171|/iredadmin') (callable not found or import error)
Nov 8 13:39:49 mx1 iredadmin[1065]: --- no python application found, check your startup logs for errors ---
Nov 8 13:39:49 mx1 iredadmin[1065]: [192.168.0.249] GET /iredadmin 500 104 "-"
Nov 8 13:41:48 mx1 iredadmin[1065]: Traceback (most recent call last):
Nov 8 13:41:48 mx1 iredadmin[1065]: File "/opt/www/iRedAdmin-1.8.1/iredadmin.py", line 8, in <module>
Nov 8 13:41:48 mx1 iredadmin[1065]: from libs import iredbase
Nov 8 13:41:48 mx1 iredadmin[1065]: File "/opt/www/iRedAdmin-1.8.1/libs/iredbase.py", line 5, in <module>
Nov 8 13:41:48 mx1 iredadmin[1065]: import web
Nov 8 13:41:48 mx1 iredadmin[1065]: ModuleNotFoundError: No module named 'web'
Nov 8 13:41:48 mx1 iredadmin[1065]: unable to load app 0 (mountpoint='192.168.0.171|/iredadmin') (callable not found or import error)
Nov 8 13:41:48 mx1 iredadmin[1065]: --- no python application found, check your startup logs for errors ---
Nov 8 13:41:48 mx1 iredadmin[1065]: [192.168.0.249] GET /iredadmin 500 104 "-"