MMS works with wifi, does not work on 4G

Bug Reports
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16

Vodafone Cable here sets me to
IPv4 77.20.107.4
IPv6 2a02:8109:8000:51:8ff:857a:eebe:9df7
(I had to ask Kabel Deutschland for the IPv4 address, too.)

The IP## I sent before where on Vodafone mobile.