503 Service Unavailable only for new files

Hello all.

I was unable to find anybody on the net affected with this problem that
I have.

Svn repositories are accessed via WebDAV, here's the Apache conf part:

<Location /repo/project_test>
  DAV svn
  SVNPath /var/svn-repos/project_test
  AuthType Basic
  AuthName "Subversion Repository"
  AuthUserFile /etc/apache2/svn_ttt.passwd
  Require valid-user
  SSLRequireSSL
</Location>

Auth file (/etc/apache2/svn_ttt.passwd) is set properly.

All files are owned by www-data, and group owned by subversion group.

I am able to checkout, update, modify file, but when I try to add a
file, I get this message:

$ svn ci -m 'Test 2'
Adding test2.txt
svn: Commit failed (details follow):
svn: Server sent unexpected return value (503 Service unavailable) in
response to PROPFIND request for '/repo/project_test/!
svn/wrk/b2972884-c634-446e-87d6-df8f4fef1d16/test2.txt'
svn: Server sent unexpected return value (503 Service unavailable) in
response to PROPFIND request for '/repo/project_test/test2.txt'

What could be the issue here?

Thanks in advance.

-- 
Nikola Kotur
nikola.kotur_at_etondigital.com