Dead battery
Keypad batteries drain faster in heat.

Remotes and controls
An outdoor keypad can stop working because of a dead battery, a lost code, the opener's lock mode or sun and moisture damage. Most causes are easy to check before booking service.
Short answer
Replace the keypad battery, then try your code again slowly. If the keypad lights up but the door does not move, check the opener's lock mode and reprogram the keypad. If the buttons are cracked or unresponsive, the keypad may need replacing.
Keypad batteries drain faster in heat.
The opener may have been reset and forgotten the keypad.
The opener's lock mode disables keypads and remotes.
Sun and moisture can wear buttons and seals. See keypad service.
Keypads sit outside in sun, dust and occasional rain, so they live a harder life than remotes kept in a car. On west-facing doors in the Inland Empire, the cover can fade and the button membrane can crack within a few years. If the keypad is old and worn, a new compatible unit is often simpler than chasing intermittent faults.
Describe what the door is doing when you call. A provider may ask follow-up questions, but a reliable price normally needs an on-site look rather than a phone-only quote.

Wireless keypads mount outside beside the door and send a coded signal to the opener.

Remotes send a coded radio signal to a receiver in the opener.

An opener only moves the door; it should never be doing the heavy lifting.
The keypad may have lost its pairing, the opener may be in lock mode or the code may have changed. Reprogramming often fixes it.
It varies with use and temperature. In hot climates, batteries may need replacing more often. Replace them if the keypad becomes dim or slow.
Strong sun can fade covers, wear button membranes and shorten battery life. A keypad in partial shade usually lasts longer.
Most keypads are reset by pressing the opener's learn button and then entering a new code on the keypad. Follow your manual.
Usually not on its own. If remotes and the keypad fail together, the opener's receiver may be the cause.
If the buttons are worn or cracked, or it no longer pairs with the opener, a new compatible keypad is often simplest.

Call to schedule a technician visit with an independent provider who serves your area.