Answer:
Rise of nationalism and economical crisis
Step-by-step explanation:
After WW1 many countries, especially in Europe, but also some in Asia, such as Japan were not satisfied with the consequences of WW1. Germany believed that a peace treaty that was signed was a national shame. Also, in some other countries the national feelings were suppressing the democratic values.
When the economical crisis hit the world at the end of 1920s it was a right moment for national leaders to proclaim dictatorship regimes in many countries, such as Yugoslavia, Spain, Portugal, etc.