Brand New Install - Can't Log In Via Admin

[cdoninger]

I'm getting " Authorization code mismatch. Are you accessing this function correctly? Please go back and try again."

I can not log in via the initial admin login and password via any method or browser or computer/phone.

I've read other threads regarding this error, but I can't find one where the admin can't log in to the admin side or front end.

[Mostafa.Shiraali]

this error is belong to wrong my_post_key  value and usually happened because bad theme coding and this parameter is missing for example make sure belong variable exist in headerinclude template

<script type="text/javascript">
.....
var my_post_key = "{$mybb->post_code}";
......
</script>

if you are login with a popup login form check that form template.



Note : if you not found solution for and if you want I can fix problem for you as non-free service , for more information reads signature.

[cdoninger]

this error is belong to wrong my_post_key  value and usually happened because bad theme coding and this parameter is missing for example make sure belong variable exist in headerinclude template

<script type="text/javascript">
.....
var my_post_key = "{$mybb->post_code}";
......
</script>

if you are login with a popup login form check that form template.



Note : if you not found solution for and if you want I can fix problem for you as non-free service , for more information reads signature.

Where do I find the headerinclude template?   I have since uninstalled and re-installed, and am able to log into the admin side, but still get the error on the front end.

I am looking at "Header Template" and do not see anything called headerinclude, and in the header itself there is no script 

I'm using the default install template and theme, I have changed absolutely nothing.

[bv64]

headerinclude:

ACP --> Templates --> [choose Template Set] --> Ungrouped Templates --> headerinclude

Link to your page?

[cdoninger]

headerinclude:

ACP --> Templates --> [choose Template Set] --> Ungrouped Templates --> headerinclude

Link to your page?

Thank you! 
The variable to be "added" was already in there.  Again, this is a fresh install version 1.8.38

These templates:

• header_welcomeblock_guest
  
• member_login
  
• portal_welcome_guesttext
  

All have:

<input name="my_post_key" type="hidden" value="{$mybb->post_code}" />

and template "error_nopermission" doesn't appear to have a place for the above:

{$lang->error_nopermission_guest_1}
<ol>
<li>{$lang->error_nopermission_guest_2} <a href="member.php?action=login">{$lang->login}</a> | <a href="member.php?action=register">{$lang->need_reg}</a></li>
<li>{$lang->error_nopermission_guest_3}</li>
<li>{$lang->error_nopermission_guest_4}</li>
<li>{$lang->error_nopermission_guest_5}</li>
</ol>


Beyond that, still stuck with original error.

Link to page:  https://popconunity.com

[cdoninger]

I still need help with this, but have an additional observation.

I have removed and reinstalled myBB several times into its own root directory, but only when I install it into a subdirectory does it function as expected with no login issues. I do not want it to be in a subdirectory if I can avoid it. Any thoughts on why this may be? It is a base untouched 1.8.38 installation, it works if in its own subdirectory, but NOT if it is in the root of the domain's html.