I descided to try another way to change to osclasspoint version. And I made upgrade to new EVO version ( some of you will remember my issues ). After that I have uploaded the last Osclasspoint Osclass version and now I cant log in to the admin pannel. SOme suggestions ?

At first few attempts I've got no errors, after disabling cache plugin now each time ( even after turned cache plugin back on ):
Invalid CSRF/Security token.
P.S. I think is a problem with the cache plugin, but have no clue how to delete the cache. I will stop the plugin with renaming the folder, but how to remove the cache.

I have tried to log in like user, no problem with all tested accounts.
 And.... no error_log is empty. Actually I have error there but its old one and I know about the problem it is a different storry, but if you want to see the error:
[31-Mar-2021 22:29:11 Europe/Sofia] PHP Fatal error:  Uncaught PHPMailer\PHPMailer\Exception: Invalid address:  (to):  in /home/oc-includes/vendor/phpmailer/phpmailer/src/PHPMailer.php:1082
Stack trace:
#0 /home/oc-includes/vendor/phpmailer/phpmailer/src/PHPMailer.php(1004): PHPMailer\PHPMailer\PHPMailer->addOrEnqueueAnAddress('to', '', '')
#1 /home/oc-includes/osclass/utils.php(489): PHPMailer\PHPMailer\PHPMailer->addAddress('', NULL)
#2 /home/oc-content/plugins/osclass_pay/email.php(176): osc_sendMail(Array)
#3 /home/oc-content/plugins/osclass_pay/model/ModelOSP.php(1311): osp_email_expired(Array, Array)
#4 /home/oc-content/plugins/osclass_pay/index.php(658): ModelOSP->purgeExpired()
#5 /home/oc-includes/osclass/classes/Plugins.php(40): osp_hourly_cron()
#6 /home/oc-includes/osclass/helpers/hPlugins.php(31): Plugins::runHook('cron_hourly')
#7 /home/oc-includes/osclass/cron.php(70): osc_run_hook('cron_hourly')
 in /home/oc-includes/vendor/phpmailer/phpmailer/src/PHPMailer.php on line 1082
[31-Mar-2021 22:37:17 Europe/Sofia] PHP Warning:  current() expects parameter 1 to be array, null given in /home/oc-includes/osclass/emails.php on line 1258

Errors you added are related to mails.
To remove cache, delete plugin and upload new fresh version.
I do not think problem is with cache, try to reupload osclass files and make sure to set backoffice theme to omega (could be done on database level, admin_theme in t_preference).

I bringed back to the version that I was using before yours came ( EVO version ) for some reason no clue what, with no changes made I cant change almoust anything in the admin. Users can register and post ads, but after few days they cant log back in. I still need the damn plugin to export users, ads and cathegories... Please do something this is fcking HELL!

I understand from all that the mess is unfixable because of different versions of different dev and their oc version buggs they havent fixed etc.... The sht is too big t obe fixed. There is a need from a payd plugin for exporting users, categories and ads.'

It is useless to pay 500 $ for themes and plugins for a not working website. Website losing now 15 precent users which means money for me ( no job ) and my clients ( no income from the websites ). I tried everything. Stoping plugins, deleting plugins ( also deleted the cache plugin ), no difference in any actions the error log is empty even the email error is not appearing now. Problem is that It is not website in similar situation that came after using idiotic upgrades ( clients wish all to be update because of security issues and modernisation - bullsht ).

I am now trying to find original ( real original ) 3.8 version of osclass. Nothing in my mind to try more right now.

What you describe as problem with login happened to me some time ago when experimenting with BCRYPT length, when it was changed to less than 8 (faster login), passwords were not working anymore.
So what I did to login into backoffice was to create new user with password ie admin123 and then copied in database s_password column content into my record.
I would check also t_admin table if its structure match to what is in struct.sql of osclass.
You can export data from database directly or ie use rest api plugin to stream data out of osclass.
As last, you should have backup before any upgrade, it is essential part of upgrade process.

I wasnt experimenting. But Users are not able also to login, this appeared after few hours of using the upgrade. not at the time .

Quote: You can export data from database directly or ie use rest api plugin to stream data out of osclass.

Have no clue how to use rest api with OC and how t odo that.

I am doing backups but sadly I see problems after a whyle of working with the website, douring that time there are users registering and posting ads... When tried to backup to 3.8 first time, no problems that much. Then found EVO version, liked it, tested it on test instalation for a day It worked fine... and then tried to upgrade to your version all websites and problems growed up more.

Tell me how to do the "stream" or whatever to make a fresh new instalation and import users, ads and categories.

Update:
Erm..... The login problem appeared to this other client website as well.... Now I have two client websites with same problem, different hostings, different configuration... The second website is using only your free plugins. No caching plugin to the second website.... He Was build directly with your OC version, previous version, the website is few months old... So I thing the problem is serious.

In This website since I havent Log out and I am there more often I am still able to go in admin without need to log in. But when User tries to log in... No success... And one more thing it redirects to the main page, no error message, and as well error_log of this website is empty also.

...Another weird thing that also happens on both websites is IF I put the url to user dashboard: website.com/user/dashboard It is showing that user is logged in. In some menus It shows error Not logged in, in others I am able to see ads and make changes to user profile.... All symptoms are on both websites... I will Upgrade another one client website to checkout if the same problem appear there too.

@pipetko
Upgrade may be often risky, you never know what will go wrong. Try with clean osclass installation or send us way how to reproduce problem on demo.

Another website with same problem. I have client with the website free - markt (dot) de. Same issues there. After login as user the website does nto shows any indications I am logged in. I have to press contact page, open an ad or something in order to show up in the menu buttons for dashboard etc. Also I CANT log in as admin. When I pressed Login button after few tries i wait for 5 minutes and directly type in browser website/oc-admin and then I am logged in. Website was with original 3.8 version only thing that I updatet was all osclasspoint plugins with last version, but that was few months ago..... Weird thing... I think stil it is from cache plugin ( it is combined with minify plugin in all places ). But It may not be from osclass. I am now thinking for may be coocies or hosting issue.

@pipetko
Login is based on cookies & sessions, cache plugins are based on storing files as cache. Minify plugin only combine CSS and Javascript. There is no cache in backoffice.
I would especially take a look on session.

I remembered that I have a client with another website using your osclass version with free plugins instalation. I tested there to reproduce the problem, but the website was working correctly. He is on a different hosting from me and my clients. I think for now is a problem in hosting. I contacted them already will see what will happen.

Changed hosting unfortunately with 4.3.2 still unable to login in admin, but able to log as user

Now for few of my client websites which are on my friends hosting the problem appeared to be from the hosting it self, not Osclass related. Now I have to solve the problem with the OC instalation on different hsoting, still unable to log in as admin, but no problems as user. I will have another try after few days.

Try with http instead of https, try to recover your password as well.