What type of TPLINK router are you using?

Can you share the settings of the mobile connection? 

What are the dhcp settings of your router? 

Possible solution:

You can try to use apn portalmmm.nl instead of apn internet. 

Apn portalmmm.nl is only IPv4.

With apn internet you can use IPv4 or IPv6 depending on the pdp-type.

Is the sim een 06-number or a 097-number, called data-sim @Hanni8al .

You need a datasim with a 097-number for your TP-Link .

A 06-number is not allowed.

@Neville I have a TL-MR6400

Here are my settings from WAN-Interface and LAN-Settings:

The settings are looking fine. I would expect that this should work. Are still having problems?

You could also try apn advancedinternet. With this apn your router is directly connect to the internet and gets a public IPv4 address.

I have only a Internet Connection with the Settings Ipv6.

With the APN advancedinternet it doesen’t work too.

With my Vodafone Sim Card works the router perfect.

@N.N. i have a 06 Number. It that the problem? I become the sim card in the Shop but i sayed that i need a sim card for my Router.

@Hanni8al Please change "Network Mode” to "4G Only”, "Authentication Type" to CHAP and put somethings in fields Username/Password

@TDN it doesn’t work too.

Maybe i cancel the contract and go to Odido or Vodafone.

@Hanni8al It doesn't work too with APN=internet of APN=advancedinternet with the CHAP-settings?

@TDN  No it doesen’t work

@Hanni8al 

For my holiday I have bought a TP-LINK mr6400.

When I use apn internet and set pdp-type on IPv4/IPv6 and connect my mobile phone (Android) with wifi. My mobile is not able to browse the internet. My laptop which has a wired connection to the TP-LINK works fine. I can see the IPv6 address in TP-LINK and when I go to ipv6-test.com it shows a public IPv4 address and IPv6 address.

When I change the pdp-type to IPv4 using apn internet. Connect my phone via wifi it works fine. Also my laptop wired is working fine. I only do not have an IPv6 address when I check ipv6-test.com website. Which is as expected. 

When I change between pdp-type I had to disconnect the cable of my laptop and reconnect the cable to the TP-LINK otherwise it stopped working for my laptop. No internet available.

I was thinking about your sonos system as it does not connect with the internet when you use pdp-type IPv4/IPv6 or IPv6 like my Android phone. Advice use apn internet pdp-type IPv4 save the configuration and reboot the TP-LINK. When the TP-LINK is up and running check if your sonos has an internet connection. Instead of rebooting the TP-LINK you can also try to power off and on your sonos. I think when you change the TP-LINK settings the connected devices some how loose there internet connection. Like my laptop. 

Hope that this works for you. :-)