I think you should ask this question to Ultimate members plugin support. These avatars come from UM plugin. So UM plugin affects forum user plugins and adds its own. You can try Leira Letter Avatar plugin and (after installation go to the plugin settings and enable the letter avatars): https://wordpress.org/plugins/leira-letter-avatar/

I deactivate the UM plugin now and will not use it anymore. And now the register and login page is Wpforo default page, I think it works better. The loading speed is faster when I click it. Thanks!

Posted by: @kevintian

May I ask that is required all the time after I did some change in the dashboard?

No, it's not required.

Posted by: @kevintian

If I did not , how long does it take to become effective in general?

You should see the change immediately if you don't have other cache plugins. If you have other cache plugins you should exclude wpForo forum page from them. Here is the instruction: https://wpforo.com/community/faq/wpforo-and-cache-plugins/

Posted by: @kevintian

The default avatars are blank now, it is too ugly. Do you have any other method?

I think you should ask this question to Ultimate members plugin support. These avatars come from UM plugin. So UM plugin affects forum user plugins and adds its own. You can try Leira Letter Avatar plugin and (after installation go to the plugin settings and enable the letter avatars): https://wordpress.org/plugins/leira-letter-avatar/

Dashboard > Forums > Dashboard and click the button.

May I ask that is required all the time after I did some change in the dashboard?

Because I recall that sometimes when I changed something, it will become effective the next day, instead of becoming effective immediately. I never used before and thought that it was server latency.

If I did not , how long does it take to become effective in general?

1.  I know that I was using wpForo's own login/registration pages before I found ultimatemember is a plugin and install it. So the problem is I have no idea why my default wpForo's own login/registration pages became to show . Could it be that I have once changed the "Custom Authorization URLs" 

Yes, it should come from the "Custom Authorization URLs" option. In any case please go to Dashboard > Forums > Dashboard and click the button.

Also, go to Dashboard > Appearance > Menus. Select the forum menu and check the login/register items.

Posted by: @kevintian

2. When I found this issue, I have tried to find some method to fix it on Youtube and learned "shortcode", I go to the "Register page" and add the shortcode_, it did not fix the issue. Is there anything wrong with my understanding?

This is not a regular shortcode. Don't use it in page content or with square brackets. These are used in the Custom menu URL field as it's shown in the documentation: https://wpforo.com/docs/root/getting-started/forum-menu/

https://wpforo.com/wp-content/uploads/2016/08/wpForo-menu-item-shortcode-custom-link.png

Posted by: @kevintian

3. If I would like to use wpForo's own login/registration pages back, what should I do? Delete the UM plugin and then? Now almost all user avatars show blank, I guess it is because UM plugin does not have the avatars like wpForo's do before.

I'm sorry but I there is no way to regenerate avatars in forum.

The question is that:

1.  I know that I was using wpForo's own login/registration pages before I found ultimatemember is a plugin and install it. So the problem is I have no idea why my default wpForo's own login/registration pages became to show . Could it be that I have once changed the "Custom Authorization URLs" 

2. When I found this issue, I have tried to find some method to fix it on Youtube and learned "shortcode", I go to the "Register page" and add the shortcode_, it did not fix the issue. Is there anything wrong with my understanding?

3. If I would like to use wpForo's own login/registration pages back, what should I do? Delete the UM plugin and then? Now almost all user avatars show blank, I guess it is because UM plugin does not have the avatars like wpForo's do before.

wpForo doesn't have any relation to your login page, as far as I see you use the UM plugin login page, so please contact to UM support: https://wordpress.org/support/plugin/ultimate-member/

wpForo has its own login/registration pages, they can be accessed with the following links, they don't require any page:

• Login: example.com/community/?foro=signin
• Register: example.com/community/?foro=signup

This morning I have got an email that people say he can not log in because the login page disappeared.

So I click the login and the page shows:

I do not know, because I did some adjustments to the Dashboard yesterday.

So I am not clear what happened. Maybe I put some URL in the attached picture but did not use any plugin for register.

I use the WPforo for my forum, and the register/login page is just what looks like in this forum. 

Please help me go back to the page. thanks.