Streaming bridge to receive feed worldwide also with full mobile set up (4G or 5G)

Hi everyone,
I’m trying to set up a full mobile to mobile link between my micro fly kit built with an atem mini extreme pro+MR1100 Netgear and a mobile receiving unit built with a streaming bridge, a VPN router (GL.iNet MT1300), a 4G router LTE12 from Mikrotik and of course, an HD monitor (but also a secondary HD Atem fly kit when needed).
Well knowing the fact that streaming bridge requires a static IP, i have provided to get an account with one of the thousand static ip organisation available on the net in combination with the VPN router above able to receive the stream via openVPN and the port forwarding as required, but still I can’t get the signal at the output because the streaming bridge shows always “port forwarding error” message. Anyone here can suggest where i’m missing? Thanks in advance!