I have a subscription of F1TV. At home, with my MT router, I can't start the stream. I access the site, I press play, I wait a few moments and I get the previous page again, where I'm expected to press play. If I connect to a VPN (usually my workplace), I can start the stream with no issue. After the stream starts I can disconnect the VPN. No issues. This happens with any machine connected to my LAN and with any browser. This happens without firewall rules and with generic (google or cloudflare) DNS server. This happens always!!!

Now, I'm not blaming MT or even my specific MT configuration. In all truth, I have no idea where the problem may rely. I have no clue on what to look for.
Can someone point me in any direction? The right one would be preferable, but at the place I am, any direction will do.....

thanks

I assume by "if I connect to a VPN (usually my workplace)" you mean that you're at home and connect to the workplace using the VPN, which redirects all connections of your PC, including the internet ones, via the workplace network. If so, I can imagine two possibilities:

• an MTU issue, which the VPN works around,
• some geoblocking at F1TV side which doesn't recognize the public IP, behind which your home LAN is hidden, as a permitted one.

What is the WAN connection of your home, PPPoE or something else? What's the overall topology between the fibre or cable from the ISP and your Mikrotik?

I assume by "if I connect to a VPN (usually my workplace)" you mean that you're at home and connect to the workplace using the VPN, which redirects all connections of your PC, including the internet ones, via the workplace network. If so, I can imagine two possibilities:

• an MTU issue, which the VPN works around,
• some geoblocking at F1TV side which doesn't recognize the public IP, behind which your home LAN is hidden, as a permitted one.

What is the WAN connection of your home, PPPoE or something else? What's the overall topology between the fibre or cable from the ISP and your Mikrotik?

You assume correctly.
It can't be geoblocking. The F1TV guys were the first ones I contacted about the issue. And they did waste a long time trying to figure it out. Among many tests, they asked for my IP Address......

I have a fiber router from the ISP. I can not dismiss it. This router is configured with no firewall, no NAT, no nothing, just DMZ to the MT router. If I turn its wifi ON and test the connection to F1TV with my laptop connected to it, then I have no issues.

So, I guess that leaves us at MTU.....
My MT is a hexS (RB760iGS). I connect to it via either an unmanaged Gbit switch or via a hapAC when I use wifi.

So, I guess that leaves us at MTU.....

Yeah, but in such case the Mikrotik itself must have an issue with MTU when forwarding between two plain Ethernet interfaces, which sounds strange to me. So when sniffing at both the LAN and the WAN interface, you should see a large packet not being forwarded from WAN to LAN.