ODOO 12 server error regarding invoice sequencing - database

Question

I am trying to change the sequence of my invoicing. Instead of resetting it each new year, I can keep the count going upwards continuously.
(for example)
inv/2021/0001 date 1/1/2023   (this one should be 2366)
inv/2021/2365    date 31/12/2022
researching on the subject I found out I need to go into technical -> sequences to get the invoice numbers I want.
but my problem is, once i click sequences I get the following server error:
Error:
Odoo Server Error
Traceback (most recent call last):
File "/odoo/odoo-server/odoo/api.py", line 1039, in get
value = self._data[key][field][record._ids[0]]
KeyError: 254
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/odoo/odoo-server/odoo/fields.py", line 981, in __get__
value = record.env.cache.get(record, self)
File "/odoo/odoo-server/odoo/api.py", line 1041, in get
raise CacheMiss(record, field)
odoo.exceptions.CacheMiss: ('ir.sequence(254,).number_next_actual', None)
During handling of the above exception, another exception occurred:
Traceback (most recent call last):
File "/odoo/odoo-server/odoo/http.py", line 656, in _handle_exception
return super(JsonRequest, self)._handle_exception(exception)
File "/odoo/odoo-server/odoo/http.py", line 314, in _handle_exception
raise pycompat.reraise(type(exception), exception, sys.exc_info()[2])
File "/odoo/odoo-server/odoo/tools/pycompat.py", line 87, in reraise
raise value
File "/odoo/odoo-server/odoo/http.py", line 698, in dispatch
result = self._call_function(**self.params)
File "/odoo/odoo-server/odoo/http.py", line 346, in _call_function
return checked_call(self.db, *args, **kwargs)
File "/odoo/odoo-server/odoo/service/model.py", line 97, in wrapper
return f(dbname, *args, **kwargs)
File "/odoo/odoo-server/odoo/http.py", line 339, in checked_call
result = self.endpoint(*a, **kw)
File "/odoo/odoo-server/odoo/http.py", line 941, in __call__
return self.method(*args, **kw)
File "/odoo/odoo-server/odoo/http.py", line 519, in response_wrap
response = f(*args, **kw)
File "/odoo/odoo-server/addons/web/controllers/main.py", line 904, in search_read
return self.do_search_read(model, fields, offset, limit, domain, sort)
File "/odoo/odoo-server/addons/web/controllers/main.py", line 926, in do_search_read
offset=offset or 0, limit=limit or False, order=sort or False)
File "/odoo/odoo-server/odoo/models.py", line 4589, in search_read
result = records.read(fields)
File "/odoo/odoo-server/odoo/models.py", line 2791, in read
vals[name] = convert(record[name], record, use_name_get)
File "/odoo/odoo-server/odoo/models.py", line 5117, in __getitem__
return self._fields[key].__get__(self, type(self))
File "/odoo/odoo-server/odoo/fields.py", line 985, in __get__
self.determine_value(record)
File "/odoo/odoo-server/odoo/fields.py", line 1098, in determine_value
self.compute_value(recs)
File "/odoo/odoo-server/odoo/fields.py", line 1052, in compute_value
self._compute_value(records)
File "/odoo/odoo-server/odoo/fields.py", line 1043, in _compute_value
getattr(records, self.compute)()
File "/odoo/odoo-server/odoo/addons/base/models/ir_sequence.py", line 96, in _get_number_next_actual
seq.number_next_actual = _predict_nextval(self, seq_id)
File "/odoo/odoo-server/odoo/addons/base/models/ir_sequence.py", line 68, in _predict_nextval
self.env.cr.execute(query % {'seq_id': seq_id})
File "/odoo/odoo-server/odoo/sql_db.py", line 148, in wrapper
return f(self, *args, **kwargs)
File "/odoo/odoo-server/odoo/sql_db.py", line 225, in execute
res = self._obj.execute(query, params)
psycopg2.ProgrammingError: relation "ir_sequence_1000015" does not exist
LINE 6: FROM ir_sequence_1000015
I believe it could be a database error but I am not sure what this is about. Any idea?
Thanks!