[Dovecot] dovecot ignores entries in virtual_alias_maps when using dovecot lda

hello list, i need help. dovecot dont look into my virtual_alias_maps . i set via postzfixadmin an alias postmaster@domain.tld to newmail@domainother.tld. when i send mails to postmaster@domain.tld mails are rejected. dovecot authworker tells me in log: user unknown. but i can request the data via postmap -v -q postmaster@domain.tld mysql:/etc/postfix/mysql_virtual_alias.cf and get result "newmail@domainother.tld".

any ideas, hwo to get dovecot to look into my alias maps?

marko