When a connections has ipv4.may-fail=yes (the default), NetworkManager
stops trying DHCPv4 after the timeout (45 seconds) if IPv6 succeeds in
See also bug 1503587 which fixed a similar problem but only for DHCPv4
renewals, not for the initial activation attempt.
Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.
For information on the advisory, and where to find the updated
files, follow the link below.
If the solution does not work for you, open a new bug report.