For some reason all meta tags are missing
I was wondering why few months I get errors for missing canonical tag, but they've all gone

There is no title, description and canonical meta tags on free websites and only canonical tag on websites with payd plugins. Now there is two differences
On websites with payd plugins and themes with activated cache plugin all meta are mising in the code
BUT on websites with free default oc theme and options ( ocpoint repo ) ONLY the canonical meta tag is missing.

For the websites with premium plugins I am thinking that there is something going on with the cache plugin. I will try on some of the websites with off cache plugin to see whats the difference

I noticed canonical tag is missing, but it should be present on search page only

I noticed canonical tag is missing, but it should be present on search page only

It should be present everywhere as it was before. because a duplicated content is imenent on some search which will show similar ads, ads in multiple categories, ads shown on user profile will be the same as ads shown in search page user ads..... SO there it is duplicate.. I have numerous errors in GS console showing exactly what I say, on each of those client websites are similar and causing similar problems. And athere are again already loss of traffic because of duplicate content, non indexed pages because of missing canonical tag etc etc. This is urgent and needs to be fixed.
https://developers.google.com/search/docs/advanced/crawling/consolidate-duplicate-urls

Quote:
A canonical tag (aka "rel canonical") is a way of telling search engines that a specific URL represents the master copy of a page. Using the canonical tag prevents problems caused by identical or "duplicate" content appearing on multiple URLs.

So .. I turned off Cache plugin on one of the client websites and meta title, meta descriptuon have appeared in the end code. No canonical tag

@pipetko
Problem is that osclass does not have mechanism to identify canonical URL.
I.e. even this URL would be considered as canonical:
/search/sOrder,dt_pub_date/iOrderType,desc/pattern,test/category,for-sale

That is not correct. Right now, only pagination (page numbering) will trigger to generate canonical URL.
So good question is, that what actually should be considered as canonical and what is not canonical anymore.

@pipetko
Problem is that osclass does not have mechanism to identify canonical URL.
I.e. even this URL would be considered as canonical:
/search/sOrder,dt_pub_date/iOrderType,desc/pattern,test/category,for-sale

That is not correct. Right now, only pagination (page numbering) will trigger to generate canonical URL.
So good question is, that what actually should be considered as canonical and what is not canonical anymore.

I am confused... I am not talking only about searches only. But before the new versions the canonical tags ware working good. So on searches there is no need for a cannonical tag ( except the search page without generasted search - the default one ), but canonical tags should be on ads, pages, blog posts and publis user profies. They are important like the index, no index, follow, nofollow tags as well. I mena just check what is wrong with a thing that was working and now it is not.

I see many of the people here actually are not checkling all those important things by some reason may be because websites are small, have no clue. But my main job is SEO ( I make the webesites for my clients for free, they pay you for themes and plugins and they pay me for SEO and in the package is a free website maintenance. So i watch all things. I dont do this for bad but in order you to make a better product. I also mentioned that you should make changes with the premium plans for a better profit which will motivate you to make a better product ...Sometimes I am wrong, I know this but I am a human So again. there is a problem with those tags and for a SEO purpouse theuy should be checked. I am telling this because it was not only on one website but on multiple client websites with different configruations. I have only one client that has no problems.... the one that never wanted to update the version of OC, and he i still tiwh the old versions of your themes and plugins aand with the last known produced original OC. He does not have any functional problems at all. A well perfect working website... But other clients wanted upgrades to be " in touch with the new things in the world ".

@pipetko
What is need to have canonical tag i.e. for:
https://demo.osclasspoint.com/for-sale/electronics/samsung-led-XYZinch_i16

if you open it and you get redirect (301) to:
https://demo.osclasspoint.com/for-sale/electronics/samsung-led-32inch_i16

Why would you care? No impact on seo, there is 301.

I am not aware there would be canonical tags somewhere else than search page.

I  think you do not understand me quite well.

Just check an old not updated OC with old version of your theme equals the time for example last known official version of OC. Check the outsorce code. Do the same with newer version with all updated things. And chechk the meta data. I think then you will completely understand what I mean.

THIS (QUOTE ):
What is need to have canonical tag i.e. for:
https://demo.osclasspoint.com/for-sale/electronics/samsung-led-XYZinch_i16

if you open it and you get redirect (301) to:
https://demo.osclasspoint.com/for-sale/electronics/samsung-led-32inch_i16

Is when url changed. After the 301 redirect the NEW URLS should have the canonical url fo the new link, and also tags index do follow all a long twith meta title meta description. Meta keyword is useless with the new google algorythms. Meta Keyword is usefull only on the main page and the other STATIC pages, not the products / ads.

I am telling you again. From all my clients there is ONLY one that is still running the last official OC version, also from the same time he didnt want to update plugins, themes etc... And the website from SEO perspective runs good ( well not fast, but... ), no SEO errors at all, only the standart schema org errors ( they should be also resolved in future, but for now not urgent ). All meta data is correct.

@pipetko
https://demo.osclasspoint.com/for-sale/electronics/samsung-led-XYZinch_i16 has 301 redirect to https://demo.osclasspoint.com/for-sale/electronics/samsung-led-32inch_i16 , canonical tag has same meaning there as other meta tags. It's permanent redirect.

Meta keywords are not used by google maybe from 2016 or so.