Hello,
@flebourse suggestion is what I would check first - make sure the PDP type (configured in mob1s1a1 interface) is not set to IPv6 only.
However, another possibility is that your operator is using 464XLAT transition technology. It was briefly discussed here:
If that’s the case, then RUT200 currently does not support address translation on it’s own, thus if IPv4 is enough for you, just set the PDP type to IPv4-only and your operator should issue an IPv4 address.
Best regards,