@German93, could be either a channel problem (CPEs support only outdoor channels) or a distance problem (too short).

You should be able to connect with the client directly to the public AP over a distance of 30m. If this does not work, it won't work neither with a CPE since the public AP's signal might be too weak to send somethingback to the CPE (e.g. if the public AP is an indoor AP).

Next issue is with antenna beam width: the CPE610 has a directional 9º wide antenna beam which concentrates RF energy into one direction. This makes it diffcult to connect to any other device other than directional CPEs. Usually CPEs are always used pair-wise for PtP links.