Click to open each section for troubleshooting tips:

How to check browser version and/or update 

Open the Safari browser. On the menu bar in the top left corner, click the Safari menu, then select About Safari. A box will open that contains the browser’s version number. The first number is the major version of Safari, the number inside the parenthesis is the build version.

How to clear browser cache, cookies, and temporary internet files 
What is Cache?
Cache is a place on your computer where active data is temporarily stored to shorten access times. In other words, cache keeps data that is frequently requested and accessed by the system. It is, therefore, saved in dedicated quick-to-access storage to reduce the time taken to retrieve the data. Results? Better latency and improved I/O (input/output). This has a direct impact on app performance, as most applications are dependent upon input and output operations.
Web Browser Cache
In web browsers, for example, frequently visited webpages are cached to improve performance. To load a webpage, your browser will then be able to access locally stored data, instead of having to request it be sent again. To see cached data at work, try clicking the back button to go back to the previous page. Your browser will be able to recover most of the files it requires from the cache. It will also read cache at a far quicker rate than reading the files from the webpage again. Why do you need to clear cache?
While cache is beneficial by design, it isn’t perfect. Its imperfections can lead to an opposite effect and cause issues with forms, logins or even entire webpage data. This happens when cached data gets outdated or altogether corrupted. The browser then wastes time trying to fetch corrupted data or reading an old item from the cache. An immediate solution to the issue is to clear out the cache and let your browser rebuild a new one.
How do I clear my browser cache on a pc?
Quick Tip:With any browser open on your Windows operating system, press the following keys (simultaneously) to quickly access the options for clearing the browser’s history:
The fastest way to clear your cache on a MAC with Safari is to use following shortcut: [CMD] + [ALT] + [E].
To learn more about clearing your browsing history, cookies, and cache, visit Apple Support.
How to add a website as a trusted site 
In the Safari app on your Mac, use Websites preferences to customize how you browse individual websites.
  • To change these preferences, choose Safari > Preferences > then click Websites.
  • On the left, click the setting you want to customize – for example, Camera.
Do the following:
  1. Choose settings for a website in the list
  2. Select the website on the right, then choose the option you want for it.
Additional preferences can be set on websites, for more information visit Change Websites preferences in Safari on Mac. For overall additional help, visit Apple Support.
Block or Allow pop-ups in Safari 
What are pop-ups?
You can prevent webpages from displaying pop-up windows.
  1. In the Safari app on your Mac, choose Safari > Preferences, then click Websites.
  2. Click Pop-up Windows.
  3. Block pop-up windows for:
A website in the list:
Select the website in the right column, then choose the option you want.
For all others: 
Click the “When visiting other websites” pop-up menu in the bottom-right corner of the pane, then choose the option you want.
You can see all the websites you’ve customized under Configured Websites. If you don’t see Configured Websites, either you haven’t customized a website yet, or you’ve cleared the list. To configure a website, see Change Website’s preferences.
All websites:
Make sure no websites are listed under Configured Websites (to clear the list quickly, select the websites, then click Remove). Click the “When visiting other websites” pop-up menu, then choose the option you want.
If you choose Block and Notify for pop-up windows on a website, click the icon in the Smart Search field to display the pop-up windows.
For additional information, please visit Apple Support.
Enable/Disable Cookies 
The process for configuring cookies in Safari on macOS perform the following steps:
  1. Open the Safari browser
  2. Click the “Safari” menu option, located at the top left of your screen.
  3. In the menu that opens, click Preferences
  4. In the Preferences screen that opens, click on the Privacy tab.
  5. On the Privacy Preferences tab, you will see the “Website tracking” and “Cookies and website data” checkboxes.
Enabling to prevent cross-site tracking blocks third-party cookies from being set, as well as third-party websites from storing data on your computer. Enabling this option is a good step in helping prevent companies from tracking your activity online.
Enabling Block all cookies will block First-Party, as well as Third-Party cookies. Enabling this may cause websites to not work properly, and Safari will warn you about this if you choose this option.
A good balance of setting is to enable Prevent cross-site tracking and disable Block all cookies.
If you click the Manage Website Data button, you’ll see a list of website domains that have stored data on your computer. You can remove some or all of them.
Once you have configured your cookie blocking preferences, you can close the Preferences window and continue using Safari.
Flash player 
Note: Adobe will end support of Flash Player on December 31, 2020. How to enable Flash for Max OS X 10.11, macOS10.12, and later:
  1. Open Safari and choose Safari > Preferences.
  2. Click the Websites tab and scroll down to the Plug-ins section. Locate the Adobe Flash Player entry.
  3. Click the checkbox to enable Flash Player.
  4. Select a setting to use for Flash Player when you visit other websites.
  5. You can configure Flash for individual websites (domains). Select a website listed in this window, and choose Ask, Off, or On.
  6. Exit Preferences after you finish configuring Flash Player.
Refresh the browser.
How to enable Flash for Max OS X 10.10:
  1. Open Safari and choose Safari > Preferences.
  2. Click the Security tab. Ensure that Enable JavaScript and Allow Plug-ins are selected. Click Plug-in Settings.
  3. Select Adobe Flash Player. From the “When visiting other websites” menu, choose On, and then click Done.
  4. For each website in the list, choose On.
  5. Click Done to save changes.