3/4G networks and
redirect-gateway def1
often don't play nice; 3/4G networks tend to assign private IPs (10.x, 192.x range) yet the default GW is often a public IP. OpenVPN gets confused by this and 'redirect-gateway' then no longer works.
To verify that this is indeed happening, comment out 'redirect-gateway' and try connecting again. If that works then you/we need to come up with a workaround. If that also does not work, then something else is going on.
In both cases, add
verb 4
to the client config and post the (sanitized) client log file when connecting.
