Using multiple authentication providers giving error in Spring Boot application

I have user details maintained in different internal_users and external_users DB tables. For that I am creating two different authentication providers, for various flow of authentication. Below is the code that is giving error:

@Configuration
@EnableGlobalMethodSecurity(
        // securedEnabled = true,
        // jsr250Enabled = true,
        prePostEnabled = true)
public class WebSecurityConfig {
    @Autowired
    private internalUserDetailsServiceImpl internalUserDetailsService;
    @Autowired
    private externalUserDetailsServiceImpl externalUserDetailsServiceImpl;

    @Autowired
    private AuthEntryPointJwt unauthorizedHandler;
    @Autowired
    private PasswordEncoder passwordEncoder;

    private static final String[] AUTH_WHITELIST = {
      "/api/auth/**",
      "/swagger-resources/**",
      "/swagger-ui/**",
      "/v3/api-docs",
      "/v2/api-docs",
      "/webjars/**"
    };

    @Bean
    public AuthTokenFilter authenticationJwtTokenFilter() {
        return new AuthTokenFilter();
    }

    @Bean
    public AuthenticationManager authenticationManager(AuthenticationConfiguration authConfig) throws Exception {
        return authConfig.getAuthenticationManager();
    }

    @Bean
    public DaoAuthenticationProvider externalUserauthenticationProvider() {
        DaoAuthenticationProvider externalUserAuthProvider = new DaoAuthenticationProvider();

        externalUserAuthProvider.setUserDetailsService(externalUserDetailsServiceImpl);
        externalUserAuthProvider.setPasswordEncoder(passwordEncoder);

        return externalUserAuthProvider;
    }

    @Bean
    public DaoAuthenticationProvider internalUserAuthenticationProvider() {
        DaoAuthenticationProvider internalUserAuthProvider = new DaoAuthenticationProvider();

        internalUserAuthProvider.setUserDetailsService(internalUserDetailsServiceImpl);
        internalUserAuthProvider.setPasswordEncoder(passwordEncoder);

        return internalUserAuthProvider;
    }

    @Bean
    public SecurityFilterChain filterChain(HttpSecurity http) throws Exception {
        http.cors().and().csrf().disable()
                .exceptionHandling().authenticationEntryPoint(unauthorizedHandler).and()
                .sessionManagement().sessionCreationPolicy(SessionCreationPolicy.STATELESS).and()
                .authorizeRequests().antMatchers(AUTH_WHITELIST).permitAll()
                .antMatchers("/api/test/**").permitAll()
                .anyRequest().authenticated();

        http.authenticationProvider(internalUserAuthProvider())
         .authenticationProvider(externalUserAuthProvider());

        http.addFilterBefore(authenticationJwtTokenFilter(), UsernamePasswordAuthenticationFilter.class);

        return http.build();
    }
}

I am getting below issue:

Handler dispatch failed; nested exception is java.lang.StackOverflowError

On further debugging I found that the controller, where below code is used, authenticationManager is showing an error as shown in image attached

Authentication authentication = authenticationManager.authenticate(
    new UsernamePasswordAuthenticationToken(authDTO.getUserName(), authDTO.getPassword()));
SecurityContextHolder.getContext().setAuthentication(authentication);

On commenting out any one of the authentication providers, the code is working, but not working with both authentication providers. Below is working code with one authentication provider

@Configuration
@EnableGlobalMethodSecurity(
        // securedEnabled = true,
        // jsr250Enabled = true,
        prePostEnabled = true)
public class WebSecurityConfig {
    @Autowired
    private internalUserDetailsServiceImpl internalUserDetailsService;
    @Autowired
    private externalUserDetailsServiceImpl externalUserDetailsServiceImpl;

    @Autowired
    private AuthEntryPointJwt unauthorizedHandler;
    @Autowired
    private PasswordEncoder passwordEncoder;

    private static final String[] AUTH_WHITELIST = {
      "/api/auth/**",
      "/swagger-resources/**",
      "/swagger-ui/**",
      "/v3/api-docs",
      "/v2/api-docs",
      "/webjars/**"
    };

    @Bean
    public AuthTokenFilter authenticationJwtTokenFilter() {
        return new AuthTokenFilter();
    }

    @Bean
    public AuthenticationManager authenticationManager(AuthenticationConfiguration authConfig) throws Exception {
        return authConfig.getAuthenticationManager();
    }

   /*@Bean
    public DaoAuthenticationProvider externalUserauthenticationProvider() {
        DaoAuthenticationProvider externalUserAuthProvider = new DaoAuthenticationProvider();

        externalUserAuthProvider.setUserDetailsService(externalUserDetailsServiceImpl);
        externalUserAuthProvider.setPasswordEncoder(passwordEncoder);

        return externalUserAuthProvider;
    } */

    @Bean
    public DaoAuthenticationProvider internalUserAuthenticationProvider() {
        DaoAuthenticationProvider internalUserAuthProvider = new DaoAuthenticationProvider();

        internalUserAuthProvider.setUserDetailsService(internalUserDetailsServiceImpl);
        internalUserAuthProvider.setPasswordEncoder(passwordEncoder);

        return internalUserAuthProvider;
    }

    @Bean
    public SecurityFilterChain filterChain(HttpSecurity http) throws Exception {
        http.cors().and().csrf().disable()
                .exceptionHandling().authenticationEntryPoint(unauthorizedHandler).and()
                .sessionManagement().sessionCreationPolicy(SessionCreationPolicy.STATELESS).and()
                .authorizeRequests().antMatchers(AUTH_WHITELIST).permitAll()
                .antMatchers("/api/test/**").permitAll()
                .anyRequest().authenticated();

        http.authenticationProvider(internalUserAuthProvider());
         //.authenticationProvider(externalUserAuthProvider());

        http.addFilterBefore(authenticationJwtTokenFilter(), UsernamePasswordAuthenticationFilter.class);

        return http.build();
    }
}

Any clue what exactly I am missing.