Many Arduino libraries contain Setup() and Loop() functions that contain one or more Delay functions. If the sum of length of the Delay functions is greater than the time step — set under System > Simulation Properties > Range — Embed does not have time to execute one iteration of the library function. The most common way to deal with Delay functions is to encapsulate the library in a compound block and set it to execute as a background task with a local time step greater than the sum of all delays in the library.
Alternatively, you can add up the length of all delays in the library and set the Embed time step to a greater value.