How do I get my Android Galaxy Tab E to stop vibrating every 30 seconds ???

try this:
1- put your phone into safe mode
2- restart it

IF that didn't solve it try this:
1- Settings
2- personal tab
3- accessibility
4- notification reminder (switch it OFF)

Troubleshoot issues related to email on your Samsung ...

support.sprint.com/...email...Samsung-Galaxy-Tab.../...

Sprint CorporationYou may have email issues if you're unable to: Send emails; Receive emails ... Scroll to and tap My Device. ... If your Samsung Galaxy Tab 3 7.0 is still unable to connect to data, ... My rating. 1 2 3 4 5. Give us your comments. Send Cancel ...

Samsung Galaxy Tab 10.1 - Email stops syncing - Android Forum ...

https://www.androidpit.com/.../samsung-galaxy-tab-10-1-email-stops-syn...

Just bought Samsung Galaxy Tab 4 and set up my email to receive from my emailserver. ... Aug 8, 2014 2:14:33 PM via Website. Aug 8, 2014 2:14:33 PM via ...

How to change the email settings on my Samsung Galaxy Tab

support.bell.ca/.../Samsung_Galaxy_Tab.how_to_change_th...

Bell CanadaNote: Entering the wrong mail server settings can stop your Samsung Galaxy Tabfrom sending and/or receiving email. If you can't get the mail server to connect, ...

How to Receive E-mail on the Samsung Galaxy Tab - For ...

hold the power button down for 10-15 seconds to force a power off. When turning back on, hold the power button down until you either feel it vibrate or something comes up on the screen.

Hi hold the power button down for approx 30 seconds Then hold the power button down & the volume down button for 30 seconds...good luck

Well, there is a place called "Android Market" or similar.

If your desired game can be found there, simply download and install the game app and you can enjoy the fun.

If the game can't be found, or it requires a fee to play. You'll probably need to root the device. Here is a 1-click Android-Root solution for your reference.

Press and hold the power button for 30 seconds or until you see the Samsung logo.

Here's an unlocking guide.

YOU CAN GET UN OFFICIAL MOD I.E FOR ANDROID 2.3 ON YOUR GALAXY TAB.
ANDROID 3.0 IS AN DIFFERENT O/S ALTOGETHER AS IT REQUIRES DUAL CORE PROCESSORS.
TRY IN FOR SAMSUNG TAB 10.1