Error on your browser: the website sent back unusual and incorrect credentials

Normally uses encryption to protect your information when Chrome tried to connect to

.... the website sent back unusual and incorrect credentials .....

as they say, your browser has HSTS problem. 

Usually you need to make sure your Webmin configuration. Yaa, I mean this case maybe occurs on your access to port 10000. 

I thing your SSL was worked to all domain but not to Webmin, so to resolve it, you can go to /etc/webmin/miniserv.conf

add new line to that file:

inetd_ssl=1

save and restart Webmin. So you can check it with your domain such as: https://mydomain.com:10000

Problem:

Message: Array and string offset access syntax with curly braces is deprecated

Resolve:

search variable with {0} change it to [0]

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Problem:

Trying to access array offset on value of type int cell/DefaultValueBinder.php

} elseif ($pValue[0] === '=' && strlen($pValue) > 1) {

Resolve:

} elseif (0 === strpos($pValue, '=') && strlen($pValue) > 1) {

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Problem:

Fatal error: Cannot use isset() on the result of an expression (you can use "null !== expression" instead) in htdocs

A PHP Error was encountered

Severity: Compile Error

Message: Cannot use isset() on the result of an expression (you can use "null !== expression" instead)

Resolve:

change isset($param) to (null !== $param)

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