Get-SPWeb can't find the site you were looking for

Error:
PS C:\Windows\system32> Get-SPWeb -Identity "https://mysite.com/docs/"
Get-SPWeb : Cannot find an SPSite object that contains the following Id or Url: https://mysite.com/docs/.

Fix:
In the Front-End machine(s) restart the application pool "SecurityTokenServiceApplicationPool".

Sign In As Different User Option In SharePoint 2016

On the front-end server(s) open file "Welcome.ascx", located at "C:\Program Files\Common Files\microsoft shared\Web Server Extensions\16\TEMPLATE\CONTROLTEMPLATES".

Find the block with the content:
<SharePoint:MenuItemTemplate runat="server" id="ID_PersonalInformation"
Text="<%$Resources:wss,personalactions_personalinformation%>"
Description="<%$Resources:wss,personalactions_personalinformationdescription%>"
MenuGroupId="100"
Sequence="100"
ImageUrl="/_layouts/15/images/menuprofile.gif?rev=40"
UseShortId="true"
/> 

and add this on the next row:
<SharePoint:MenuItemTemplate runat="server" ID="ID_LoginAsDifferentUser" 
Text="<%$Resources:wss,personalactions_loginasdifferentuser%>" 
Description="<%$Resources:wss,personalactions_loginasdifferentuserdescription%>" 
MenuGroupId="100" 
Sequence="100" 
UseShortId="true" />

NB! The change must be made on every front-end server and always back-up!

SharePoint 2016 ports list

Protocol	Port	Usage	Comment
TCP	80	http	Client to SharePoint web server traffic (SharePoint – Office Web Apps communication)
TCP	443	https/ssl	Encrypted client to SharePoint web server traffic (Encrypted SharePoint – Office Web Apps communication)
TCP	1433	SQL Server default communication port.	May be configured to use custom port for increased security
UDP	1434	SQL Server default port used to establish connection	May be configured to use custom port for increased security
TCP	445	SQL Server using named pipes	When SQL Server is configured to listen for incoming client connections by using named pipes over a NetBIOS session, SQL Server communicates over TCP port 445
TCP	25	SMTP for e-mail integration	Cannot be configured
TCP	16500-16519	Ports used by the search index component	Intra-farm only Inbound rule Added to Windows firewall by SharePoint
TCP	22233-22236	Ports required for the AppFabric Caching Service	Distributed Cache…
TCP	808	Windows Communication Foundation communication	WCF
TCP	32843	Communication between Web servers and service applications	http (default) To use custom port, see references section Inbound rule Added to Windows firewall by SharePoint
TCP	32844	Communication between Web servers and service applications	https Inbound rule Added to Windows firewall by SharePoint
TCP	32845	net.tcp binding: TCP 32845 (only if a third party has implemented this option for a service application)	Custom Service Applications Inbound rule Added to Windows firewall by SharePoint
TCP	32846	Microsoft SharePoint Foundation User Code Service (for sandbox solutions)	Inbound on all Web Servers Inbound rule Added to Windows firewall by SharePoint Outbound on all Web and App servers with service enabled.
TCP	5725	User Profile Synchronization Service(FIM)	Synchronizing profiles between SharePoint 2013 and Active Directory Domain Services (AD DS) on the server that runs the Forefront Identity Management agent
TCP + UDP	389	User Profile Synchronization Service(FIM)	LDAP Service
TCP + UDP	88	User Profile Synchronization Service(FIM)	Kerberos
TCP + UDP	53	User Profile Synchronization Service(FIM)	DNS
UDP	464	User Profile Service(FIM)	Kerberos change password
TCP	809	Office Web Apps	Intra-farm Office Web Apps communication.

References:
https://blog.blksthl.com/2013/02/21/tcpip-ports-of-sharepoint-2013/ (Stole it from here)

Configure diagnostic logging in SharePoint 2016

Configure diagnostic logging location in SharePoint 2016 with PowerShell.

Example:
Change the location for Diagnostics log(ULS):
set-SPDiagnosticConfig -LogLocation “D:\Logs\ULS”

Disk space:
Set-SPDiagnosticConfig -LogDiskSpaceUsageGB 500

Change the location for Usage and Health log:
set-SPUsageService -UsageLogLocation “D:\Logs\Health”

Get current log levels:
Get-SPLogLevel

Set category to default:
Clear-SPLogLevel

References:
https://technet.microsoft.com/en-us/library/ee748656(v=office.16).aspx

ULS Viewer best tool for viewing SharePoint errors

ULS Viewer

ULS Viewer is a Windows application that provides a simplified view of ULS log files in SharePoint 2013 that supports aggregation, filtering, sorting, highlighting, append, and more. 

Dowload:
https://www.microsoft.com/en-us/download/details.aspx?id=44020

Deafult log location:
C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\16\LOGS\

Visual:

Scan open ports using CMD.exe

Open cmd.exe and run "netstat -an".

Parameters:

• -a   : Displays all active TCP connections and the TCP and UDP ports on which the computer is listening.
• -e   : Displays Ethernet statistics, such as the number of bytes and packets sent and received. This parameter can be combined with -s.
• -n   : Displays active TCP connections, however, addresses and port numbers are expressed numerically and no attempt is made to determine names.
• -o   : Displays active TCP connections and includes the process ID (PID) for each connection. You can find the application based on the PID on the Processes tab in Windows Task Manager. This parameter can be combined with -a, -n, and -p.
• -p   Protocol   : Shows connections for the protocol specified by Protocol. In this case, the Protocol can be tcp, udp, tcpv6, or udpv6. If this parameter is used with -s to display statistics by protocol, Protocol can be tcp, udp, icmp, ip, tcpv6, udpv6, icmpv6, or ipv6.
• -s   : Displays statistics by protocol. By default, statistics are shown for the TCP, UDP, ICMP, and IP protocols. If the IPv6 protocol for Windows XP is installed, statistics are shown for the TCP over IPv6, UDP over IPv6, ICMPv6, and IPv6 protocols. The -p parameter can be used to specify a set of protocols.
• -r   : Displays the contents of the IP routing table. This is equivalent to the route print command.
• Interval   : Redisplays the selected information every Interval seconds. Press CTRL+C to stop the redisplay. If this parameter is omitted, netstat prints the selected information only once.
• /?   : Displays help at the command prompt.

Is the port status "LISTENING" indicated that the port is opened?
Yes. It means that some service is listening to that port on your computer for incoming connection i.e. this port is open for establishing new connections.

References:
https://technet.microsoft.com/en-us/library/bb490947.aspx

SharePoint AppFabric Error Failed to connect to hosts in the cluster

Error:
ErrorCode<ERRCAdmin040>:SubStatus<ES0001>:Failed to connect to hosts in the cluster

OR

cacheHostInfo is null

OR

A failure occurred in SPDistributedCacheServiceInstance::Provision. cacheHostInfo is null for host 'SPSERVER'.

Fix:
Check if your "Distributed Cache" servers can connect to each other trough ports „22236“, „22234“, „22235“ and „22233“.

References:

• https://habaneroconsulting.com/insights/distributed-cache-needs-ping
• https://msdn.microsoft.com/en-us/library/ee790914(v=azure.10).aspx
• https://technet.microsoft.com/en-us/library/cc262849(v=office.15).aspx