iwpd user missing

[nullpunkt]

hi

the iwpd user is missing for a httpdocs of one domain. if i recreate it manually in windows it works.
the problem is, that .security-file is also crashed.

so i delete .security-file and launch permission check in plesk panel.
the report tells me that i it found one issue with security problems.

after that, the security-file is created, but iwpd-user is missing again.

what should i do?

btw:
ftp-logon to e.g subdomain is possible, but i cannot change inside the httpdocs-folder.

best regards
nullpunkt