Seems to me like a network loop. Not sure because network topology isn't clear from your description.

You should always use two CPEs to create a stable directional link. You could connect to your Archer (indoors?), too, but expect unstable and slow link then, because the Archer might have a weak signal over 200 ft - not the CPE. What's more, the CPE uses 5 GHz outdoor channels, while indoor APs most often use indoor channels (depends on your country's regulatory domain). 

This is the typical scenario for connecting two distant places over a directional wireless link between two CPE510:

MalC123, you're welcome. Great that it works now, have fun with the CPE!

jalmeidam wrote

But works the archer a6 like this? Only with a ethernet cable from the cpe510 to the router a6 yo share wireless Internet?

A router can be connected to the remote CPE, too, but your LAN behind the router will be a separate subnet unrelated to the network the PtP link is part of. You can share Internet this way, yes, but not devices on the local network.

You could also use a router as an access point. To do so, disable the DHCP server on the router and connect the remote CPE by cable with one of the LAN ports (not WAN!) of your router. In this mode you can share devices on the same network the PtP link is part of.