Input box of password has id userpassword and autofill is not working

1P_Tommy thank your for the fast response. I tried again to create a new entry but still the password stays empty on autofill.

If I create a new entry, also the password field stays empty and the actual password is put into an additional password field:

If I keep it like this or add the password to the password field has not affect on the autofill.

The site is the login page of my Zyxel router in my network. I did also noticed that the password will be removed from the input box as soon also you click in it again after entering.

Here is the html of the username and password div:

<div data-v-161e09a8="" id="Login-login" class="container-fluid padding-large">
<form data-v-161e09a8="" class="form-login form-small formbox loginbox">
<h5 data-v-161e09a8="">Login</h5>
<div data-v-161e09a8="" class="form-group ">
<div data-v-161e09a8="" class="row">
<label data-v-161e09a8="" for="username" class="col-12 nopadding">User Name</label>
<div data-v-a8844a60="" data-v-161e09a8="" class="zyinputBox col-xl-12 col-lg-12 col-md-12 col-sm-12 col-10 nopadding">
<input data-v-a8844a60="" data-outline="" type="text" id="username" errorinline="true" placeholder="" maxlength="32" autocomplete="off" class="form-control form-control-lg">
</div>
</div>
<div data-v-161e09a8="" class="memo"></div>
</div>
<div data-v-161e09a8="" class="form-group last-rows">
<div data-v-161e09a8="" class="row">
<label data-v-161e09a8="" for="userpassword" class="col-12 nopadding">Password</label>
<div data-v-311a916d="" data-v-161e09a8="" class="zypasswordBox col-xl-12 col-lg-12 col-md-12 col-sm-12 col-10 nopadding">
<input data-v-311a916d="" maxlength="128" maskctrl="true" data-outline="" id="userpassword" type="text" autocomplete="off" errorinline="true" class="maskPassword form-control form-control-lg">
<input data-v-311a916d="" maxlength="128" maskctrl="true" id="userpassword" data-outline="" type="text" autocomplete="off" errorinline="true" class="unmaskPassword form-control form-control-lg" style="display: none;">
<i data-v-311a916d="" id="userpassword_maskCheck" class=" icon-visibility-on"></i>
</div>
<div data-v-161e09a8="" class="memo"></div>
</div>
</div>
<div data-v-161e09a8="" class="clearfix"></div>
<div data-v-161e09a8="" class="btnbox ctext">
<button data-v-161e09a8="" id="loginBtn" type="button" class="normalbtn disabled" disabled="disabled">
<span data-v-161e09a8="">Login</span>
<div data-v-161e09a8="" class="bg-block"></div>
</button>
</div>
</form>
</div>