There is one possible WARNING that states "Number of iterations on CS-integration too low" when performing the Recalculation in RM Bridge Analyzer. The number of iterations is only one possible hint if no equilibrium can be found within the Ultimate Check. The Iteration Control is part of the parameters to govern the convergence of the iteration process in the Cross-section integration at the ultimate load capacity checks and reinforcement design. . For Ultimate Load Capacity Check and Reinforcement design a certain number of iterations will be needed for determining the equilibrium state. These definitions can be found at the Extended Settings in the Recalculation Pad, available in the Advanced options as shown below.

As this is one possibility, there are several other possibilities so check also if you have defined proper reinforcement groups (reference sets of the type "bending" or "longitudinal") in the tension zones of the cross-section.