Why i can't install apk's ?

[Pab10_Suarez]

Model Name: Asus zenfone live L1 (ZA550KL (2gB RAM
Firmware Version:WW_ZA550KL_15.01.2003.137_20200307
Rooted or not: NOPE

ok i was going to install a backup aplication but i can't install the apk and mi phone says "applicaiton not installed" i can't found the optionto allow unknow origins where is it?

[Pab10_Suarez]

yeah but idk efore i could install apk and now what happened?

[Pab10_Suarez]

Any mod could response?

[Christine_ASUS]

Hi Pab10 Suarez
Thank you for your asking. Kindly provide the information below so that we could better assist you.
1. Which apk you could not install? Do the issue appear after any firmware update? Does the issue only appear in this apk? (Sometimes may come from the disturbance from the installed 3rd party apps.)
2. Check internal storage space：Settings > Storage & memory
3. Restart your device
4. Clear app data/cache of Play Store：Settings>Apps & notifications > App info > Google Play Store>Clear data or Clear cache.
5. Please try "the Factory Reset" 
Setting>System>Reset>Factory data reset
Please note that once the Factory Reset is completed, all data, apps, settings and personal information will be deleted.

If you have any further queries, please do not hesitate to contact me.

[Debasish_Sahoo]

Factory reset your phone and again enable install unknown apps. Most probably it will work.
Thanks!