$ man port_associate
...
       EAGAIN     The  maximum  number of objects associated with the port was
                  exceeded. The maximum allowable number of events or associa-
                  tion  of  objects  per  port  is  the  minimum  value of the
                   process.max-port-events   resource  control   at   the   time
                  port_create(3C)  was used to create the port. See setrctl(2)
                  and rctladm(8) for information on using resource controls.

                  The number of objects associated with a port is composed  of
                  all  supported  resource  types. Some of the source types do
                  not explicitly use the port_associate() function.
...

$ man port_create
...
       EAGAIN    The  maximum  allowable  number of ports is currently open in
                 the system. The maximum allowable number of ports is the min-
                 imum  value of the  project.max-port-ids  resource control. See
                 setrctl(2) and rctladm(8) for information on  using  resource
                 controls.
...