I2C transmission problems

I am trying to communicate with a PIC microcontroller using the I2C interface using a STM32F103. I have a recurring problem: everything is fine until I run this function:
static HAL_StatusTypeDef I2C_WaitOnMasterAddressFlagUntilTimeout(I2C_HandleTypeDef *hi2c, uint32_t Flag, uint32_t Timeout, uint32_t Tickstart)
{
while (__HAL_I2C_GET_FLAG(hi2c, Flag) == RESET)
{
if (__HAL_I2C_GET_FLAG(hi2c, I2C_FLAG_AF) == SET)
{
/* Create stop */
SET_BIT(hi2c->Instance->CR1, I2C_CR1_STOP);

/* Clear autofocus flag */
__HAL_I2C_CLEAR_FLAG(hi2c, I2C_FLAG_AF);

hi2c->PreviousState = I2C_STATE_NONE;
hi2c->State = HAL_I2C_STATE_READY;
hi2c->Mode = HAL_I2C_MODE_NONE;
hi2c->Error Code |= HAL_I2C_ERROR_AF;

/* The process is unlocked */
__HAL_UNLOCK(hi2c);

return HAL_ERROR;
}

/* Check timeout */
if (Timeout != HAL_MAX_DELAY)
{
if (((HAL_GetTick() - Tickstart) > Timeout) || (Timeout == 0U))
{
if ((__HAL_I2C_GET_FLAG(hi2c, Flag) == RESET))
{
hi2c->PreviousState = I2C_STATE_NONE;
hi2c->State = HAL_I2C_STATE_READY;
hi2c->Mode = HAL_I2C_MODE_NONE;
hi2c->ErrorCode |= HAL_I2C_ERROR_TIMEOUT;

/* The process is unlocked */
__HAL_UNLOCK(hi2c);

return HAL_ERROR;
}
}
}
}
return HAL_OK;
}

this function returns an error because the PIC address is invalid, when in fact the address is correct. What could be the problem?